 Richard S. Clemens |
Problem with Sharpness I need a little advice. I am shooting pictures of birds outside my living room window (window open during shooting) in a tree in my yard. I am using a Canon Rebel Digital with a 75-300 4-5.6 IS USM lens and aperture priority 5.6 - 6.3 to knock out the background - a big red stop sign, etc. My pictures are not very sharp. Do I lose sharpness by extending this lens to 300mm? Would 200 be sharper? How much effect would the 5.6 - 6.3 aperture have on sharpness? At 300mm, I can fill my LCD with the subject. Many thanks!
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robert G. Fately |
Richard, you don't mention using a tripod, and this can very well be the main problem. When you use the lens at 300mm focal length, it's similar to using a 9 power binocular - which not only magnifies the subject 9 times; it also magnifies any shake or movement at the camera side as well. While your intent is good to use the widest available aperture, it is still not a fast lens in the first place. This means that the shutter speed will be slower than it would with, say, an f2.8 lens. Slow shutter speed means a number of things - any quick enough movement on the subject's part will appear as a blur, and any movement introduced by you at the camera end will cause blur as well. Understand, no matter how still you think you are, the blood flowing through your arteries and veins will cause a barely perceptable movement in your hands, which in turn is magnified by the longer lens. So ... use a tripod. That's rule number 1. Any stable support will be good - doesn't have to be a $500 carbon fiber behemoth. It should be sturdy, though - not a flimsy collapsible. From inside your home, a sturdy tabletop tripod or beanbag might make sense. If possible, use a shutter release as well - to keep your finger pressure from disturbing the stability. Beyond that, it's up to the shutter speed. The "rule of thumb" for 35mm cameras is 1 over the focal length should be the slowest shutter speed to handhold. With your camera's "crop factor", that multiplies a bit - so at 300mm the slowest shutter speed you should ever handhold is 1/500th - and that's a stretch. Even at 1/2000th you will see improvement using a support. Of course, if there's not enough light to expose properly at those higher shutter speeds, you must go slower, or raise the ISO (and deal with noise). If the bird's wings are flapping, then, they may become blurred.
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David A. Bliss |
Everything Bob said. I want to add one more thing. I don't know if the D Rebel has mirror lockup (my 10D does). If it does, you might want to think about using it as well. When I am shooting with my 400mm lens, I always set the camera for mirror lockup, unless I am shooting at a high shutter speed (over 1/500th). I can see a huge difference in the sharpness of my photos. The mirror moving to let light onto the sensor makes the camera shake just slightly. Locking the mirror means that the first time you push the shutter, it locks the mirror, the second time, it opens the shutter. BTW, you do not want to leave the mirror locked for very long, as it is letting light into the camera the entire time, and bright light for too long can damage the sensor. Use a shutter release cable. If I am thinking of the right lens, the lens you are using doesn't have a lens mount for the tripod, which means your camera will not be as stable when on the tripod. Just pushing on the shutter can make the camera shake enough to blur. Remember, it takes very little camera shake to make the picture seem just slightly out of focus, just enough to seem slightly soft, and not tack sharp.
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Richard S. Clemens |
Bob, thanks for the information, I will use it next time. I do have a tripod but not a cable release. I am sure I caused some movement when I pressed the shutter release. I do get a little excited. Thanks for your help.
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anonymous A. |
I think you will be a lot better off using either Program mode with shift to get a faster shutter or Tv and setting 1/500 or higher. The bean bag suggestion is both effective and practical, and a monopod might work ... But your sharpness problems might not be due to shake at all. Birds move fast! Focus is harder to achieve on a moving subject, especially with shallow depth of field; try using predictive autofocus instead of single frame. Finally, you could check the settings for sharpening in your camera and increase the amount of sharpness the camera applies, or the saturation level (which can make images APPEAR more sharp or less sharp, as can the contrast settings). These settings can also be adjusted after your files have been downloaded using the software that Canon supplies with the camera or in other software like PSP or Photoshop; adjusting the sharpness afterwards gives you more control. Perhaps if we could see some of your problem images we could offer more specific ideas about how to deal with the difficulties...
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Mary |
Re: the sharpness problem, many responses were valid, I believe. But he is using the Image Stabilizer lens (IS), so the problem is that the birds rarely are still, always moving. Take many pictures, at high speed and many times you will get lucky with a sharp picture now and then. That's my solution when I use the same equipment.
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Richard S. Clemens |
Many thanks to those that offered comment, I am currently changing the way I take those pictures. I have also ordered a cable release. Thanks for your help.
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Paul Illes |
I have found there is one aspect of long lens photography that noone mentions: that is, the way you hold the camera in hand held shots. If you see a pro shooting, they do not hold both hands on the body like most amateurs do. A pro will support the lens with one hand while the other (usually the right hand) holds the body and operates the trigger. That is much steadier than a lens hanging out there, wobbling with every pulse of your heart.
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- Craig m. Zacarelli Contact Craig m. Zacarelli Craig m. Zacarelli's Gallery |
Im useing a rebet XT and the same lens and its not too sharp at full zoom... its just not. Also, it is very slow on the AF, youd be better using Manual focus.. try it, I did and was suprised at how fast you can focus once you get the hang of it! Craig-
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Michael C. Bennett |
Here's a cool and very easy way to solve the problem. I had a problem taking photos of hummingbirds at a feeder outside my window at the cottage, and I solved it this way. Please note that the distance to subject was about ten or twelve feet. I waited for a partly cloudy day, when the light meter for 100 asa would read about f/8.5 @1/125 second. Then I put a Vivitar 285 with a Fresnel zoom on it (lets you shoot longer range with less light falloff). Flash was set for an exposure of f/16 at 100 asa, and I used 100 asa film. Lens was set at f/16. Shutter speed was 1/125th. This means that the flash will freeze the motion of the bird, and also it means that only the image made during that 1/500th of a second will be properly exposed. So any "blur" that happens between the 1/500th and 1/125th of a second, does not register on the film. It's part of the dark background. Bye bye, hand shake, camera motion, bird motion. Instant clear, brightly lit bird. Have fun. p.s. the technical details are in the design of electronic flash units for cameras. When you set the flash for a higher exposure, you're setting it for the same intensity as a lower exposure, it's just that the flash stays on for a longer period. Full power on the Vivitar 285 gives a flash duration of 1/200th of a second. 1/16 power gives you exposures lasting fractions of a thousandth of a second. Every flash is built this way.
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olivia griffin |
Richard, If I understand correctly, you have the digital Rebel XT, which is what I have. I have found the very same problem to be true. I use a tripod regularly and that helps, but there are just subjects that a tripod cannot be used for, especially unpredictable and fast moving ones. I've tried using the setting that allows the focal points to move with the object and that has helped. It's just frustrating because I see people out shooting these great pictures with no tripod and I can't seem to do it. I don't know if they're in just fully auto mode and that's why, but I just can't imagine that. In my opinion David seems to have the right idea by checking saturation and sharpness on the camera before shooting. Sometimes I wonder if it's me or the camera. I am somewhat new at this and the Rebel XT is my first real digital camera. However, I have taken some classes with it and read the mannuel book about 3 times. Anyway, sharpness is a problem for me as well. ISO, changing that has helped and the tripod have been the most helpful. It's the lower light faraway fast moving that give me the most trouble. So any suggestions would be great.
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Richard S. Clemens |
Thanks to all that offered their help to me. I now have a cable release, I know that should help. My tripod is in the living room on carpet, that does not make for the best stability. We had cloudy, rain and snow in this area so I haven't had a change to try the new suggestions. Again thanks.
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