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When in Doubt Blame your Camera:
10 tips for diagnosing your Images:

Trolling popular photo sites after buying a new camera or lens can be like browsing WebMD for diseases matching your symptoms. Frightening reports of all sorts of mishaps pop-up. Your expensive new camera might have back-focus or front-focus or bad pixels or poor color or buggy firmware or some other nearly fatal disease. But keeping in mind that there are several million healthy D-SLRs out there--just like there are several billion healthy people on the planet will help put your symptoms in perspective.

But how do you tell if you're just having some trouble using your new gear and all its settings or whether it actually has a problem? We've provided 10 tips on how to diagnose your camera or lens so you can decide what the problem is.

 

When in doubt, blame your camera: 10 Tips for diagnosing your gear

1. Troubleshoot your image

The very first step in sorting out whether you have an equipment problem is making sure you know what is wrong with your image. Often we get email or postings saying images are "out of focus" or "pixelated" or "blurry" or "dark". None of these describe a precise problem, just a symptom. As a start, the article I wrote for PC Magazine on Troubleshooting your Images will give you a start on identifying whether the problem is motion blur or camera focus or something else.
 
Once you know what the problem is you can start to identify the culprit.
 

2. Isolate "static" Focus Issues (Shoot some bottles)

Check your trouble images to see if anyplace in the image is in focus. If nothing is in focus then you probably don't have a focus issue. But if part of the foreground or background seems to be in focus then your problem may indeed be that the camera focused in the wrong place. The trick is finding out why.

There is no guaranteed way to tell when you press the shutter whether your image will be in focus. Sure it looked sharp, but if the subject is moving shutter lag can cause focus errors. And even if nothing is moving the combination of your vision and the eyepiece optics may not match what the camera lens sees.

To help isolate focus issues the place to start is shooting a row of targets. Put a set of bottles, cans, or anything else with a nice pattern up on a wall or fence ranging from near to far. Then focus on one and check the resulting image. Look at the ones immediately in front and in back. Is your focus "centered" around the object you aimed at? (Note that there is usually about twice as much of the background as foreground in focus so "centered" really means about 1/3 of the way back in the area which is in focus).

Note that at least one of the objects should be in focus. If none of them are then either your focus is way off or there is something more fundamental wrong with your setup or your camera or lens.

Repeat the experiment with different f/Stops and different lenses if you have any doubt that everything is in working order. In fact, this is a great exercise to do anytime you get a new camera or lens. For example, I found that when used with a TC-20E my 600f/4 focuses off by about 3". That's enough to make a big difference when shooting small birds, so I've learned to compensate for it.

If your camera is consistently focusing in the "wrong" place, then compare AF & manual Focus as well as different lenses to isolate whether it is the lens, AF unit, camera alignment, or perhaps the finder's adjustment in conjunction with your eyes. If the camera passes this test with flying colors but you still have focus issues with moving subjects, try step 3.

3. Isolate "Dynamic" Focus Issues

Predictive focusing on a moving target is tricky for anyone, especially for a camera which is busy blinding itself by raising the mirror to get off a shot or sequence of shots. To isolate issues when focusing on a moving target start simple. Find a stably moving subject in bright light with good contrast. Cars driving by are a great one and easy to find. Carefully pan along with the car slowly enough that the camera can track it. Then check to see if the resulting image is in focus.

The slower your camera (both in terms of shutter lag and AF speed) and the slower your lens (the larger the minimum f/Stop number) the better your technique needs to be to get good focus on moving subjects. In particular make sure and keep panning "through" the shot as the camera will be taking the image after you press the shutter.

If you're sure your technique is fine but you can't get sharp images, either you need a better camera or lens, or one or the other of them isn't working properly. Sometimes the only way to figure out which is happening is to compare the results using other similar equipment. Find a friend who has the same camera you do, or perhaps impose on the dealer where you purchased the camera to let you experiment with another one.

While you're at it you'll want to double-check the focus modes. 99% of the time I use "shutter priority" (some vendors call it something else) focus because I want the camera to take the shot as quickly as possible when I press the shutter, but you can also use the "single" or "focus priority" mode for this experiment to see if the camera thinks it is locking on at all.

If your focus is working on your test subjects then try recreating the lighting or contrast conditions you're having trouble with. As light levels decrease or background contrast decreases AF systems (and our eyes for MF) have more trouble focusing. You may find yourself needing to pre-focus before tracking the subject or not able to focus on some subjects at all.

4. Isolate Resolution / Sharpness Issues (Shoot a newspaper)

If your camera appears to be focusing correctly but your images are still blurry, then there may be a sharpness or resolution problem. Tape a newspaper page to a wall in a well lit area and photograph it with the lens and camera combination you're using. If you need to use a slow shutter speed make sure and use a tripod. If it is a long lens make sure and use proper long lens technique.

DigitalPro PHOTO TIP: You can test your long lens technique by doing the newspaper experiment with both a cable release & while holding the camera yourself while gently resting your left hand on the lens barrel over the tripod mount. If you're technique is good the image you take while your body is damping the camera and lens vibrations will be sharper than the one taken with the remote!

With a properly aligned camera and correctly working lens the newspaper should be sharp and more or less readable (depending on the size of type) from corner to corner. Of course the corners will be slightly further away so if you have limited depth of field then they may be slightly out of focus.

If there are major variations in the readability of the text then either your lens may have severe aberration issues or your camera mount may have been knocked out of alignment. That is not uncommon with current model cameras as in the quest to save weight the mounts are quite light and thin. Correcting the mount alignment is about a $300 repair although if you're in doubt then your vendor should be willing to check the alignment for you for free or for a small fee as part of having it cleaned and checked.

Note that carrying the camera and a heavy lens by the camera strap will contribute to alignment issues. So will having baggage handlers drop your photo backpack while the camera is attached to a long lens (I speak from experience unfortunately)

5. Isolate Lens Issues (Experiment with Lenses

Less likely than camera problems are sudden problems with your lenses. If a lens is brand new then it might be out of spec so if it is giving you trouble see if you can shoot it side by side with another sample of the same model. Lens performance, like camera performance, is often very subjective so be particularly careful to compare similar images at similar settings. Zoom lenses usually have different characteristics at the wide (short) and long ends, with many being a little soft at the full extent of their range. Some of that is a normal part of having a convenient zoom range. Similarly lenses also have different performance at varied apertures. Typically they are at their sharpest around f8 to f11, although "pro" lenses are normally sharp throughout most or all of their range.

BCNH
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So if you think you're having problems with a lens, see if the issue is isolated to certain focal ranges or apertures and then compare your findings with reviews of the lens to see if what you're seeing is just the normal performance of the lens or something wrong with your particular unit.

6. Avoid Consensual Hallucination

Every new camera and lens triggers a salvo of problem reports which seem to spread across the web like wildfire. If you have a problem it is re-assuring to be able to search for similar problems and find out quickly that others share the issue. But if you're not sure what is happening problem reports can lead you in a dozen different and distracting directions. The key is to be specific and selective about how you interpret problem reports you find on the web.

First, is the source of the problem report a reliable one or are they always griping about something? Second, do they have experience with other similar gear so that they really understand what is happening? Third, do they have an axe to grind? Some photographers are paid by sponsors or rely on controversy to drive up their site ratings. Make sure you're getting information from someone who understands and has shot with the gear at issue in situations similar to those you need to make work.

7. Isolate viewing and printing problems

Any method of evaluating images involves some assumptions about the processing and viewing environment. Printing an image assumes that you have a printer which can accurately render the original capture. Viewing one on the computer assumes you have an accurately profiled monitor. And trying to evaluate an image in the camera LCD is normally asking for trouble. So before your blame your camera for the image you see on your monitor or print make sure you have a color correct (ideally a color-managed) workflow from end to end and that your images are accurately tagged with or converted from the camera's native color space.

Remember that any viewing or printing system, no matter how well designed or expensive, is dependent on viewing conditions. Color profiles are only accurate for images displayed in the conditions for which they were built. A common problem is to look at images created using a daylight profile in dim indoor lighting. Of course they will look dark and be labeled as under-exposed if no correction is applied.

8. Identify Raw processing problems

If you shoot Raw there is even more potential for confusion. On average a flaw you see in a processed image is more likely to come from your raw file processor or one of its settings than from your camera or lens. For test shots I always shoot both Raw and JPEG images so that I can get a general sense of how the camera is performing from the JPEG and then see the extremes of performance by processing the Raw image.

9. Identify Flash Issues

Digital flash has been a can of worms since its inception. Everything that we thought we knew about TTL flash with film had to be re-invented by the camera companies and relearned by photographers for digital. So just because your flash doesn't work like it did with film doesn't mean its broken. Finally with the newest flashes and the newest digicams flash performance is back close to where it was at the height of film.

If you're concerned your flash unit is not working correctly, make sure the batteries are charged and then experiment with different settings & power levels. If you can find one that works for your test image then most likely you're just seeing design issues with the flash when you have difficulties and not a physical problem with the flash itself.

10. Send it in

If you've followed all these tips and it really seems like the problem is your gear, send it in for a check-up or repair. It won't get any better sitting on your shelf. If you think it is malfunctioning and you don't send it in then you won't have any confidence in it and it is guaranteed to bug you the entire time you use it. If you're a working pro, NPS (for Nikon) or CPS (for Canon) may be able to help you with a loaner while they have it for repair.

 

 

 

 

 

 

 

 

 

 

 


 


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