Showing posts with label Photography. Show all posts
Showing posts with label Photography. Show all posts

Friday, 8 April 2011

Photography Exposed Podcast - 006 - Hoender-Shift vs Lens Baby, Punt-en-skiet vs DSLR, & Lens huur

PhotographyExposed.tv - skryf in op ons iTunes voer! Christopher Stokes bespreek die besluit om 'n goedkoop punt-en-skiet kamera te bring op' n reis na Italië. Brian praat oor lens seleksie en hoe om te bepaal wat jy nodig het. Vir 'n foto reis na Pittsburgh en Cleveland, Brian huur' n Canon 24mm TS-E Tilt Shift lens, en bespreek die verskille tussen wat dit gebruik en 'n goedkoop Lens Baby. Leërskare Brian Palmer Christopher Stokes Video Produksie: Nancy Cross Post Production & MotionGrafiese: Brian Palmer Podcast klankbaan tema: Covox - Densha die leërskare: Brian Palmer Christopher Stokes Video Vervaardiging & Post: Brian Palmer Podcast klankbaan tema: Covox - Densha Lapse footage (Carbon) Jim-Box www.youtube.com

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Monday, 20 September 2010

Using Nikon Equipment For Wildlife And Nature Photography


Image : http://www.flickr.com


Choosing the Right Digital SLR for Your Nature Photography

It is very true that it doesn't matter what equipment you use -- it's what you do with the camera that matters. However, there is no question that when you're hiking through a thick jungle in the middle of central america you want to pack light. Even though the Nikon D2x has the prestige of being Nikon's premier "PRO" camera, you may not find it's the best fit for your nature work.

One of the first things you need to consider is how you're going to use the pictures. Look up the magazines you want to publish your work. Send in for "submission guidelines" and find out their minimum mega pixel count. The same is true for stock agencies -- browse around and decide which place you'd ultimately like to sell your work. Many organizations have their submission guideliens published on their websites. If you're more interested in learning and doing nature photography for your own pleasure then by all means buy the less expensive models. There's nothing wrong with a camera that takes a 5 or 6 megapixel image. You'll still be able to blow it up to poster size if you want a special print made.

Choosing the Right Digital SLR for Your Nature Photography

It is very true that it doesn't matter what equipment you use -- it's what you do with the camera that matters. However, there is no question that when you're hiking through a thick jungle in the middle of central america you want to pack light. Even though the Nikon D2x has the prestige of being Nikon's premier "PRO" camera, you may not find it's the best fit for your nature work.

One of the first things you need to consider is how you're going to use the pictures. Look up the magazines you want to publish your work. Send in for "submission guidelines" and find out their minimum mega pixel count. The same is true for stock agencies -- browse around and decide which place you'd ultimately like to sell your work. Many organizations have their submission guideliens published on their websites. If you're more interested in learning and doing nature photography for your own pleasure then by all means buy the less expensive models. There's nothing wrong with a camera that takes a 5 or 6 megapixel image. You'll still be able to blow it up to poster size if you want a special print made.


Magnification - Use it to your Advantage

For wildlife photographers in particular, the one advantage of shooting with any Nikon digital camera these days is the magnification factor. Rather than create a sensor the same size as one frame of 35mm film, Nikon and most other digital SLR camera manufacturers decided to create a sensor that is smaller than the 24x36mm standard frame of the older film models. Having a smaller sensor means you aren't going to capture all the information on the left and right and top and bottom of the frame. This may sound really bad... but there is no need to worry about what you haven't captured because the viewfinder has been adjusted so that what you see optically is what is captured in the digital file.

The result is that the camera multiplies the magnification of all the lenses. Nikon's magnification (depending on the camera you use) is around 1.5x. That means a 300mm lens is now magnified to 450mm. This is great news for wildlife photographers. The only drawback is that wider angle lenses (like a 17mm wide angle becomes a 25.5mm not-as-wide-angle lens. However, landscape photographers still have some options. I'll get to those in a bit.

Choosing the Right Lenses

Unfortunately, no one can tell you which lenses to buy or "how to build the perfect SLR system for nature photography." Again, it depends on the kinds of photos you like to take, your personal preference and the market where you want to sell your image.

The great advantage of Nikon cameras is that you can use older lenses on your body. This allows a lot more freedom of choice and means you can get really amazing older lenses at shockingly affordable prices.

I'll give you an example. One of my favorite lenses is a 300mm f4 manual focus prime lens from the 1970s. It cost only $350 CAD (meaning it would be much less expensive in American dollars) and the glass is still ED! Nikon especially developed ED (Extra-low Dispersion) glass to provide pricise optical colour correction. This special glass (not available in all Nikon lenses) provides the sharp, clear resolution required for superb photographs. The other advantage (at least for me since I generally hike to find wildlife) is that it weighs less and packs small.

Another example -- the 50mm 1.4 auto focus lens (that's right f1.4!) sells for only $166 CAD (again, much less in American dollars). It's actually an 80mm on your body. That means you have a prime lens at 80mm that can take pictures in the darkest settings. And, because Nikon has been perfecting its 50mm lenses since its inception as a company (Nikon used to include a 50mm on all its bodies until well into the late 1980s), it's one of Nikon's very best lenses. It's cheap because 50mm on a 35mm camera is kind of pooey. But 80mm on a digial camera is marvelous. edit
edit caption:
Magnification - Use it to your Advantage

For wildlife photographers in particular, the one advantage of shooting with any Nikon digital camera these days is the magnification factor. Rather than create a sensor the same size as one frame of 35mm film, Nikon and most other digital SLR camera manufacturers decided to create a sensor that is smaller than the 24x36mm standard frame of the older film models. Having a smaller sensor means you aren't going to capture all the information on the left and right and top and bottom of the frame. This may sound really bad... but there is no need to worry about what you haven't captured because the viewfinder has been adjusted so that what you see optically is what is captured in the digital file.

The result is that the camera multiplies the magnification of all the lenses. Nikon's magnification (depending on the camera you use) is around 1.5x. That means a 300mm lens is now magnified to 450mm. This is great news for wildlife photographers. The only drawback is that wider angle lenses (like a 17mm wide angle becomes a 25.5mm not-as-wide-angle lens. However, landscape photographers still have some options. I'll get to those in a bit.

Choosing the Right Lenses for your Style of Nature Photography

Unfortunately, no one can tell you which lenses to buy or "how to build the perfect SLR system for nature photography." Again, it depends on the kinds of photos you like to take, your personal preference and the market where you want to sell your image.

The great advantage of Nikon cameras is that you can use older lenses on your body. This allows a lot more freedom of choice and means you can get really amazing older lenses at shockingly affordable prices.

I'll give you an example. One of my favorite lenses is a 300mm f4 manual focus prime lens from the 1970s. It cost only $350 CAD (meaning it would be much less expensive in American dollars) and the glass is still ED! Nikon especially developed ED (Extra-low Dispersion) glass to provide pricise optical colour correction. This special glass (not available in all Nikon lenses) provides the sharp, clear resolution required for superb photographs. The other advantage (at least for me since I generally hike to find wildlife) is that it weighs less and packs small.

Another example -- the 50mm 1.4 auto focus lens (that's right f1.4!) sells for only $166 CAD (again, much less in American dollars). It's actually an 80mm on your body. That means you have a prime lens at 80mm that can take pictures in the darkest settings. And, because Nikon has been perfecting its 50mm lenses since its inception as a company (Nikon used to include a 50mm on all its bodies until well into the late 1980s), it's one of Nikon's very best lenses. It's cheap because 50mm on a 35mm camera is kind of pooey. But 80mm on a digial camera is marvelous.

Lenses - Pros and Cons

While I can't tell you the right lenses to buy for your particualr needs... I can give you some feedback/impressions about the particular lenses I am using or have used in the past.

Nikkor 10.5mm f2.8 Fisheye: I never thought such a specialized lens could provide me with so much use. For more information, I've written a short article about how to use a fisheye lens in your nature photography athttp://www.naturestocklibrary.com/gallery/2472892

Nikkor 18-70mm f/3.5-4.5G ED-IF AF-S DX Zoom - This lens is all right. I bought it as a kit lens a long time ago and it's served well for the wider range. I wish I had saved pennies and purchased a 2.8 that offered a wider range (like a 12mm to 25mm).

Tamron 17-35mm f2.8: This is a great lens but, alas, I purchased it for a film camera and the magnification on my digital body means that it isn't that useful in my photography right now. I'm planning on selling it (along with my other wide angle) and buying a 2.8 that has a wider range so I can do more with landscape photography.

Nikkor 50mm f/1.4D AF - This is the same lens I discussed earlier. It's small, has a low price tag, allows you to shoot in really dark situations and it's an 80mm on a digital camera. You really can't go wrong.

Nikkor Nikon 80-200mm f2.8D ED AF Zoom - This is a fantastic lens that stays at 2.8 no matter if you are shooting at 80 or 200mm. Again, magnification means it's actually a 300mm zoom. Zooms are great because you can adjust your focus distance depending on where your subject is located. Not so great with subjects that are always far away (like the macaws seen here), but really awesome for docile wildlife like deer. It also has a macro function that works beautifully.

Nikkor 105mm f/2.8D AF Micro, or 105 Micro for short - This is probably Nikon's most used macro lens, probably because the lens can serve triple duty. First of all, it is a macro photography lens and it allows you to take photographs at a 1:1 reproduction ratio (on a 35mm body), which means that a 24 by 36 mm subject will fill the entire frame. Second, it makes a very good general purpose short telephoto lens. Third, it is also at least a very reasonable portrait lens (although, with magnification it may be too much of a telephoto on a digital SLR). I really love this lens for macro photography.

Nikkor 300mm f4 manual focus - While a "prime" lens doesn't offer the flexibilty of a zoom... it's still an ideal choice for getting the best results in your work. This is the same lens I discussed earlier and, considering it cost only $350, it's light & the focusing is so smooth, it's one of my favorite lenses. I never leave home without it.

Nikkor 600mm f5.6 manual focus ED Glass - Again, I paid a lot less for this lens (which is actually a hefty 900mm on a digital body and also has the famous Nikon ED glass!!) because it's an older model and it's manual focus. I spent $1,599 USD - but consider that a newer model would go for at least $5,000 to $25,000, depending on the f stop. Some may argue that 5.6 is a bit too narrow of an f stop but I find the compression with telephoto lenses means that I wouldn't want to shoot a 900mm subject with anything wider than 5.6 (2.8 would make the focus far too shallow on such a far away subject). Although... for closer subjects 2.8 is magic!

In the past, I have also used the Sigma 70-300mm 3.5-5.6 and the Tamron 200-400mm 3.5-5.6 and both served well as affordable zooms while I was learning about photography. I have since sold them to pay for the lenses I currently use.

Lenses - Pros and Cons

While I can't tell you the right lenses to buy for your particualr needs... I can give you some feedback/impressions about the particular lenses I am using or have used in the past.


Nikkor 10.5mm f2.8 Fisheye: I never thought such a specialized lens could provide me with so much use. For more information, I've written a short article about how to use a fisheye lens in your nature photography at http://www.naturestocklibrary.com/gallery/2472892


Nikkor 18-70mm f/3.5-4.5G ED-IF AF-S DX Zoom - This lens is all right. I bought it as a kit lens a long time ago and it's served well for the wider range. I wish I had saved pennies and purchased a 2.8 that offered a wider range (like a 12mm to 25mm).


Tamron 17-35mm f2.8: This is a great lens but, alas, I purchased it for a film camera and the magnification on my digital body means that it isn't that useful in my photography right now. I'm planning on selling it (along with my other wide angle) and buying a 2.8 that has a wider range so I can do more with landscape photography.


Nikkor 50mm f/1.4D AF - This is the same lens I discussed earlier. It's small, has a low price tag, allows you to shoot in really dark situations and it's an 80mm on a digital camera. You really can't go wrong.


Nikkor Nikon 80-200mm f2.8D ED AF Zoom - This is a fantastic lens that stays at 2.8 no matter if you are shooting at 80 or 200mm. Again, magnification means it's actually a 300mm zoom. Zooms are great because you can adjust your focus distance depending on where your subject is located. Not so great with subjects that are always far away (like the macaws seen here), but really awesome for docile wildlife like deer. It also has a macro function that works beautifully.


Nikkor 105mm f/2.8D AF Micro, or 105 Micro for short - This is probably Nikon's most used macro lens, probably because the lens can serve triple duty. First of all, it is a macro photography lens and it allows you to take photographs at a 1:1 reproduction ratio (on a 35mm body), which means that a 24 by 36 mm subject will fill the entire frame. Second, it makes a very good general purpose short telephoto lens. Third, it is also at least a very reasonable portrait lens (although, with magnification it may be too much of a telephoto on a digital SLR). I really love this lens for macro photography.


Nikkor 300mm f4 manual focus - While a "prime" lens doesn't offer the flexibilty of a zoom... it's still an ideal choice for getting the best results in your work. This is the same lens I discussed earlier and, considering it cost only $350, it's light & the focusing is so smooth, it's one of my favorite lenses. I never leave home without it.


Nikkor 600mm f5.6 manual focus ED Glass - Again, I paid a lot less for this lens (which is actually a hefty 900mm on a digital body and also has the famous Nikon ED glass!!) because it's an older model and it's manual focus. I spent $1,599 USD - but consider that a newer model would go for at least $5,000 to $25,000, depending on the f stop. Some may argue that 5.6 is a bit too narrow of an f stop but I find the compression with telephoto lenses means that I wouldn't want to shoot a 900mm subject with anything wider than 5.6 (2.8 would make the focus far too shallow on such a far away subject). Although... for closer subjects 2.8 is magic!


In the past, I have also used the Sigma 70-300mm 3.5-5.6 and the Tamron 200-400mm 3.5-5.6 and both served well as affordable zooms while I was learning about photography. I have since sold them to pay for the lenses I currently use.

Why I LOVE and Highly Recommend Manual Focus

I used to be terrified of focusing manually. On most auto focus lenses, the focus ring is small and more difficult to use... also there's something really easy about just allowing your camera to do the focusing work for you. I was afraid I couldn't react quickly enough to moving subjects and that I wouldn't be as good as my camera's auto focus. Now I see the errors of my ways.

For wildlife (or people), you want to make sure the main subject's eyes are in perfect focus. You won't be able to sell any image if the eyes aren't in focus. If you shoot a subject 10 feet away at 2.8 and use auto focus, the camera will choose the object closer to the camera (usually the nose, cheek, or eye brow... not the eye itself). A 2.8 aperture means that you will have such a soft depth of field that the eyes will appear out of focus. The older (and more affordable) manual focus lenses have the most beautiful focusing rings you've ever seen. I find it much easier to use manual focus on my 300mm f4 lens from the 1970s than my newer autofocus 80-200mm zoom (using the auto focus feature). Unfortuately, I find the focusing ring on the newer models a little bit pooey... but I did want to make the case for why I think manual focus lenses from the 1970s are the greatest things since sliced bread!


Rule of Thumb for Fast Subjects

You may already be aware that your shutter speed should be at least the same as the distance of your lens. For instance, you need to shoot at least 1/300th of a second if you are using a 300mm lens or hand shake will make your picture look really blurry. And anything larger than 300mm should be put on a tripod (preferably one with a ball head for wildlife work). With magnification, you may be able to get away with shooting a 300mm (a 450mm on your digital) hand-held... at 1/450th of a second or higher...)in a pinch... but investing in a good ball head tripod will really improve your results if your lens is higher than 300mm.

Back on the subject of pairing your shutter speed with lens distance... if you are currently shooting P or Auto it's a good idea to change to shutter priority instead. If you're shooting with a 200mm make sure your shutter is set at 1/300 because of the magnification. All modern digital cameras will then set the aperture to pair with the shutter speed. At the same time, practicing photography on manual settings is always a good idea because it will offer you greater control.

I could write for days about shooting nature and wildlife photography with Nikon equipment but I'll stop for now. You're welcome to read more of my nature photography articles online at http://www.naturestocklibrary.com/Wildlife%20Photography%20Articles.

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Thursday, 26 August 2010

Digital Photography Tutorial - Digital Camera Filters


Image : http://www.flickr.com


Filters are plastic or glass layers placed in front of the lens of a camera to block certain light waves to reach the sensor. Although most filters are designed for DSLR lenses, generic filters can also be purchased and used together with compact digital cameras.

There are many filters out there but I am going to talk about three of the most useful types.

The first one is called the UV filter. UV stands for ultraviolet and it is the electromagnetic rays that can damage your skin and your camera sensor. If most of your photography activities are indoors then this filter may not be useful for you. But it is extremely necessary for outdoors. This filter not only protects the sensor from ultraviolet rays but it also physically protects the front of the lens. This is one of the most generic and cheapest filter but highly essential.

The second one is called the CP-L filter. This filter is actually a polarizer. The filter has a polarizer that can be rotated on a thin surface. This filter allows photographers to adjust certain light rays to pass through the lens and onto the sensor. This filter is handy to minimize reflections from a subject. For example, when shooting a lake, a polarizer may be used to reduce the reflection of the lake, enabling the camera to visibly see the fishes swimming in the lake.

The third one is called ND Grad. Filter. This is an acronym for Neutral Density Graduation filter. Unlike the previous two filters, this filter is separated into two separate regions. The filter is separated into half and one region is darker than the other. The dark region gradually becomes light as it approaches the other half. This filter is useful for landscape photography when the sky is usually overexposed to compensate the exposure of the land. This filter is use to darken the sky and balances the exposure stops between the sky and the land to produce an equally exposed subject. With this filter, the brightness range of the composure is also reduced thus solving the subject-brightness range problem in cameras

There are a few classifications for this filter. There are usually two values of an ND Grad. Filter: 0.3 and 0.6. The 0.3 filters are used for 1 stop compensation where as the 0.6 filters are used for 2 stops compensation. (Each stop is the stop difference between the sky and the land) For each value, there's soft and hard graduation from the dark region to the light region

All lens filters are also categorized with their diameter. That is all about filters now. If you have some money to spare, get a filter today and try it out! There are lots of potentials in photography when using a filter. Ask your local store for some recommendations as well.

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Saturday, 24 July 2010

Digital SLR Cameras - What's New For Military Photography


Image : http://www.flickr.com


DSLR cameras are highly valued by military photographers because of their resolution, sensitivity, versatility in the field, availability of a wide variety of objective lenses and because they allow an accurate preview of framing close to the moment of exposure. Many photographers also prefer dSLRs for their larger sensors compared to most compact digital cameras, now available with image sensors the same size as traditional film formats. These large sensors allow for similar field-of-view values to film formats, as well as their comparable sensitivity.

Over 80% of the dSLR cameras sold today are models from Nikon or Canon. As a result of their predominance, an abundance of lenses and accessories are available for these two camera bodies, resulting in an excellent selection and remarkable pricing. These accessories include: objective lenses that are fast, lightweight, optically stabilized, autofocus, as well as night vision modules and other camera accessories that increase overall camera performance. Note that while there are other camera manufacturers that provide excellent products worthy of consideration for certain applications, only Nikon and Canon cameras are mentioned in this article.

Pixels: How many? How Big?

The most noticeable change in the evolution of digital SLR cameras has been the steady increase in the number of pixels that makeup the image sensor. Commercial cameras have seen the number of pixels in the camera's sensor grow twenty times in as many years, from 1MP (1 million pixels) in 1990 to over 20MP in 2010.

Are cameras with larger sensor arrays better? Not necessarily. It depends on the application. There's more to understanding the impact of larger array sizes than merely the number of pixels. There are two other important considerations that are considered here: the physical sensor array size and the physical pixel size.

Impact of Physical Array Size

The first dSLR cameras used image sensors that were significantly smaller than traditional 35mm film formats (36mmx24mm). As shown in Figure 2, today dSLR image sensors are available in several distinct sizes. The smallest image sensors are about 2/3 the size of the 35mm format. They are available from both Canon (known as APS-C format) and Nikon (known as the DX format). Canon also provides cameras with a slightly larger size sensor, APS-H which is approximately 28x19mm. The largest sensors (known as "full-frame" sensors) are now available in cameras from both Canon and Nikon and have the same size sensor as the original film SLR cameras, 36mmx24mm.

For cameras having an image sensor that is smaller than full-frame, a digital crop factor has been defined (also known as the focal length multiplier or magnification factor) which can be calculated by taking the ratio of the diagonal dimension of 35mm film (43.3mm) to the diagonal dimension of the camera's image sensor size. As should be obvious by the term focal length multiplier, multiplying the lens focal length by the crop factor gives the effective focal length of a lens that would yield the same field-of-view if used on a full-frame camera. For the military photographer, the concept of having a crop factor >1 is normally regarded as a benefit. For long distance viewing, a narrower field of view is quite desirable and the crop factor provides photographers a "boost" in long-focal-length enabling them to fill the frame more easily when the subject is far away. For example, the focal length multiplier for a Nikon DX-format camera is 1.5. Using a 200mm lens on a Nikon DX-format camera will deliver the same field-ofview as a 300mm lens on a full-frame camera. However, while there are benefits for long distance viewing, the narrowing of the FOV is sometimes a disadvantage to photographers when a wide FOV is desired. For example, a 24mm lens on a Nikon DXformat camera will result in the same field-of-view as a 36mm lens, possibly too narrow for the application necessitating the use of expensive ultra-wide lenses to deliver the desired FOV (16mm in this example). Obviously, cameras having "full-frame" image sensors that are the same size as the 35mm film size, there is no crop factor (crop factor is 1).

Impact of Physical Pixel Size

In order to better understand the impact of the pixel size, compare the performance of two cameras that have the same physical array size but a different number of pixels (and consequently different pixel sizes). For this example, let's compare the Nikon D3X (fullframe image sensor with 24MP) and the Nikon D3S (full-frame image sensor with 12MP). For the D3X, the physical pixel dimension is about 6 micron whereas the D3S has pixels that are about 8.5 micron, about 40% larger. In this example, if the military photographer is performing surveillance at a distance, identification of objects will be related to the number of pixels on target. Hence, if the same lens is used on the two cameras being compared, the standoff distance for the higher resolution model will be further than for the lower resolution camera. Explained differently, in order for the lower resolution camera to deliver the same resolving capability as the higher resolution camera with a 300mm lens, the lower resolution camera would either need a 420mm lens or the photographer would need to move closer to the target by about 25% of the distance.

As far as resolving capability goes, smaller pixels are better and the advantage goes to the high resolution camera which can use lenses that are lightweight, easy to hold and essentially "faster". Unfortunately, more smaller pixels aren't always the best thing for a surveillance photographer! All things being equal, as pixels get smaller in size, they also become a lot less effective at gathering light resulting in lower sensitivity for the camera. Pixel sensitivity is related to the area of the pixel, so in our comparison, the pixels that are 40% larger will likely deliver twice the sensitivity (1.4x1.4~2). This means that to obtain the same light sensitivity will require an extra F-stop or double the exposure time. Alternatively, the camera's processor will have to gain-up the signal. (More on this in the next section). Nikon probably realized that for some photographers, more resolution isn't always better. Adding pixels means making them smaller and the smaller the pixel the worse the light sensitivity. Fortunately, noise reduction techniques have improved considerably in the past few years, making it possible to increase resolution while keeping sensitivity about constant. So what if you applied current noise reduction strategies to an existing sensor, without adding more pixels? That's certainly what Nikon intended with the design of the D3S, leaving the resolution at 12.1MP allowed them to increase the sensitivity for those customers that need it. For photographers who absolutely need more resolution, Nikon has the 24.5MP D3X.

Low Light Photography

For the military photographer, some of the most demanding situations occur at night when there is little ambient light, or scenes are at a distance. Today, dSLR cameras have unique capabilities and accessories are available that help the photographer make the most out of night-time imaging circumstances.

Aperture and Exposure Time

The primary factors that impact imaging in low-light are still fundamental to photography - lens aperture and exposure time. For night-time photography, since depth of field is not normally an important factor, it makes sense to select an objective lens that has the largest possible aperture. Selecting an objective lens for a specific application may be as important as selecting the dSLR camera. In fact, one may select either the Nikon or Canon body because of the specific objective lenses that are available. Similarly, exposure time for night-time imaging should be set as long as possible but still to avoid blur due to observing objects in motion or from camera jitter.

Enhanced ISO - Higher gain with drawbacks

Aperture and exposure time directly impact the amount of light that impinges on each pixel in the image sensor and affect the sensor's output electrical signal. In addition, dSLR cameras permit the photographer to adjust the gain (i.e. amplification) of the sensor's output electrical signal. (This is distinctly different from the ISO definition for film cameras which was to be adjusted to match the film sensitivity). For dSLR cameras, increasing the gain will amplify the sensor signal. Like all electrical circuits, image sensors are not perfect, and with the image signal, they also produce some noise in the form of unwanted random errors in the signal. Noise in digital images appears as graininess or specks of false color. To avoid too much noise, the night-time photographer adjusts the camera's ISO to a value that is high enough to brighten the image while still maintaining acceptable image noise levels. Today, the maximum value is typically 1600, but some cameras deliver perfectly usable images at ISO 3200, 6400 or even 12800.

In addition to the standard ISO settings, digital cameras now perform noise reduction on digital images. As a result, some additional gain-up is enabled on these cameras, sometimes one step (H1), or effectively two times the maximum ISO setting, but also two steps (H2, 4 times) and three steps (H3, 8 times). This Enhanced ISO setting is now available on most digital SLR cameras. For example, both the Canon EOS-1D Mark IV and the Nikon D3S permit three levels of enhanced ISO which results in an equivalent ISO setting of 102,400! It is important to note that images adjusted as such normally have a great degree of noise and exhibit significant degradation in resolution because of the noise reduction techniques. Apparently, as with all electronic circuits at high gain, image noise can significantly degrade image quality.

Night Vision Modules

Today's digital SLR cameras offer the photographer full control of aperture, shutter speed and ISO settings enabling the capture of excellent usable images in low light that were not otherwise possible. However, in many situations such as photographing scenes at night with very little ambient light, or telephoto photography at night at a distance, even the best digital SLR cameras simply do not have sufficient sensitivity to capture adequate images. In these situations, night vision modules are the ideal accessory.

The night vision module accessory fits between the SLR objective lens and the camera body. Simply remove the objective lens, attach the night vision module to the camera body and attach the objective lens. AstroScope night vision modules are designed to seamlessly integrate with the camera and lens combinations, maintaining all the electronic functions of the SLR objective lens (including image stabilization) via the camera's hot-shoe. The night vision module is powered directly from the camera and conveniently turns on with the initiation of the shutter release button.

The night vision module features an automatic gain control that assures that its output is relatively constant. As such, camera settings are relatively easy to configure, as follows:
• Exposure time 1/30 sec (no need to make it shorter since the intensifier has its own lag)
• Manual aperture (so that lens F-stop setting stays put)
• F-stop at widest aperture (intensifier automatically adjusts light level)
• ISO setting adjusted to a level where camera noise is not apparent
• Autofocus Off (image intensifier scintillation can confuse autofocus sensors)
• Image stabilization On (to maintain stable images while camera is in motion)

Summary

The evolution of the digital SLR (dSLR) camera continues with impressive features being added at a steady rate. For the military or law enforcement photographer, the new dSLR camera models and new features can be quite useful for portable observation and in-the-field news gathering, both at night and during the day. Some of the benefits are:

• Image sensor arrays continue to grow in physical size, now available with full-frame formats the same as the traditional film SLR cameras.

• Pixels continue to be packed more densely, increasing overall resolution and the ability of dSLR cameras to detect, recognize and identify objects at a distance.

• Sensitivity of cameras is improving, with cameras having unenhanced ISO settings up to 12,800.

• Night vision modules are available to improve light gathering by 8-10 F-stops while still permitting electronic lens functions to continue to function, including image stabilization.

DSLR cameras continue to be highly valued by military photographers over other camera styles because of their large sensors, resolution, sensitivity, versatility in the field, availability of a wide variety of objective lenses and night vision modules.

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Friday, 25 June 2010

The Magical World of Insect Digital Photography - A Digital Camera Adventure in Miniature


Image : http://www.flickr.com


When sitting in our garden or out walking in the woods we are sometimes distracted by a flying insect such as a butterfly passing us by or perhaps a ladybird beetle on her merry way, maybe even an unwelcome wasp that is trying to smell our lips to see what we had for breakfast. In our world they are many things to each of us, they make us happy, sad, or even frightened sometimes at the very sight of some of them. Yet even though they outnumber us by billions we are rarely bothered by them no matter how weird or menacing they may appear to look. That is unless of course you happen to take a real close look at what they really look like...

There are one or two ways that we can enter their world and take a closer look at these amazing creatures that have existed for millions of years. The first involves them being dead and examining them by means of a microscope, which is neither very humane nor skillful.

Another way to examine or take a closer look at them is by means of photography, which preserves their existence as well as making the whole event much more interesting. A bit like going hunting, only instead of using something as destructive as a rifle we would be using a camera lens which is a lot more creative and helps with conservation.

With modern day camera lenses even something as normal as an 18 - 75mm with macro will produce some very interesting close up images. From that there are a couple of alternatives for taking close-up images, the first is to start purchasing expensive lenses that will produce some simply amazing pictures, but for a much cheaper yet by no means tacky are lens magnifiers.

These magnifiers generally come in a selection of sizes that can all fit on the front of a lens as well as each other.

Sets tend to contain a:


1x Magnification
2x Magnification
4x Magnification and a
10x Magnification

Once we have a set of these it is simply a question of attaching to our lens and going off hunting (in miniature) some of the images that are able to be captured in this manner are sometimes beyond belief and certainly make all the effort of spending ages on our hands and knees worthwhile.

Ideally a tripod would be the chosen means of holding the camera for some great pictures, but with insect photography this is rarely possibly due to the continual movement and speed with which the insects tend to move about.

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