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7

This sort of testing is normally performed with an infinite conjugate optical system. One example of such is a/an (auto)collimator. Collimators and AutoCollimators can be used interchangably for the task of testing a lens at infinity. The testing procedure is simple. Obtain an (auto)collimator which is focused to infinity and contains a resolving power ...


5

I use DxOMark to compare technical lens data. They use a standard test process to measure and compare the following lens parameters: Resolution Transmission Distortion Vignetting Chromatic aberration These data points are taken at different focal lengths (for zoom lenses), at different apertures and are tested on a variety of camera bodies. Honestly, ...


4

You asked about basic testing of a used D90 but I have commented for DSLRs in general. Much but not all will apply to a D90 and most will be useful in most cases. If you can devise a high reliability way of doing this you can make money from it. Alas, modern DSLR camera are complex electromechanical mechanisms which have many potential ways of going wrong....


3

I think your first stop should be at Imatest, which offers many different suites of tests widely used by large commercial & industrial customers. That said they also cater for the individual, check out in particular the Imatest Master. The downside is the purchase price (although there seems to be trial version available) and you may need extra test ...


3

There's a few ways to go with this. First, you need a point of comparison, or a baseline to say what is "working" or "good enough" or "problem free". This might be something like: As good as other Olympus TG-2 cameras, i.e. is it function at it's own spec? As good as another specific camera, i.e. is it functioning as well as its peers? Reliably achieves ...


3

Producing and comparing MTF's is not really as easy as it may seem. Different manufacturers use different contexts, sensors are often tested in a different context than lenses, and direct apples to apples comparisons can be difficult. That said, the way Canon MTF charts work is fairly strait forward. The 10lp/mm MTFs are intended to measure sharpness at a ...


3

I think there were a number of real reasons for 'a look', and most of those no longer apply...but others may have taken their place. The real ones IMHO are historic. 35mm Changed Photography Leica invented 35mm and suddenly a lot of professional reportage and suchlike became infinitely more portable. This meant that there were Leica type photographs, ...


2

Ensure you test the camera at its highest possible shutter speed. Try this in both single shot and multiple shot mode. Look for any darkening of the frame that could indicate the shutter is starting to fail. Also closely inspect some shots and look for dots (like dirt) and more importantly streaks (grease or worse scratches) on the sensor. Shooting ...


2

Are "weather sealed" gear tested for how good their "weather sealing" is? AFAIK, cameras aren't tested and rated against some independent standard -- if they were, manufacturers would certainly advertise that fact. Equipment is usually described as being weather sealed if it is, and weather sealing just isn't mentioned if it's not. Equipment reviews ...


2

When I want to test the sturdiness of a tripod I put it at its hihgest position and push down on the part where the camera would go. With cheap tripods you can see the legs move away from eachother (or even bend). While pushing you can also move your hand back and forth a bit to feel if there's movement somewhere in the couplings. You will also notice ...


2

I want to compare sharpness of two lenses, consider 50mm f/1.8G vs 35mm f/1.8G from Nikon on a crop sensor camera by taking some photos (from some small size text on a paper) and review the results. Here, I don't care the perspective issues (just sharpness is important). You have an apple and an orange and you're trying to compare them. I can't think of a ...


1

I have had some cameras with lens uniformity problems, where some areas in their photos were not as sharp as other areas. Most of the time the corners weren't as sharp as the center of the image, but occasionally a camera took photos where the center was blurrier than the rest of the image. To test the lens uniformity, I printed out several pieces of paper ...


1

I need to move closer to the subject as the second one is a wider lens. When I do this, the texts are more clear on the wide angle lens. I'm not sure if this is fair for comparison, because when you are closer to a subject, you can see better details. This is absolutely fair. When you are measuring clarity, you are determining angular resolution across the ...


1

Just to give another (maybe wrong) view on this, I think what is being referred to as the Leica look is a mixture of subjective and objective things. There are some photographers that are so used to review, make, create, and study pictures taken with Leica lenses and cameras that can identify the lens a picture was taken with. I know it may seem disturbing, ...


1

I would recommend you to raise the ISO to lower the shutter speed. The old rule which says "Match shutter speed and focal lenght" come in handy here. So for a 90mm lens, you should aim to have a shutter speed of (crop factor x focal length), in this case, 90 x 1.5 ~ 135 => shutter speed around 1/135 or shorter. Since the lens also lack stabilization, this ...


1

It will be difficult under such circumstances to do anything but a cursory inspection. The best advice would be to know the lens you are going to buy and it's particular quirks. Ideally, the seller could send you a picture taken with the actual lens in advance, so you could see for yourself, barring that, if you could bring a camera and a laptop, and try ...


1

Take a look at a sample test on photozone.de. They have standardized test results available for distortion, vignetting & CA and MTF charts. (Although these might be generated by imatest.com test suite)


1

In addition to the obvious (visible scratches on the body, ability to take pictures and to autofocus), it is a good idea to check for: Number of shots already taken. A typical entry-level DSLR is tested for about 100,000 shutter actuations. See How many actuations are "too many actuations"? for more details. Dust inside the body. A quick look on ...


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