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Image sharpness
Just bought a 40D that came with the 28-135 lens package - I believe it's an f/3.5-5.6....

I also picked up the basic 70-200 Canon zoom lens (no IS) to play with....

Most of what I am shooting is sport related as both of my kids are involved in fastpitch softball and baseball..

Great camera, does everything and then some that I could want and I have no regrets on the purchase. What I am noticing though, is that the image quality, even when shooting at the highest resolution, loses a lot of crispness much past about the 60% zoom range. I suspect some of it is occuring when I crop the photos and it exagerates a slightly out of focus picture. I'm cropping maybe 50%....

So if I rely strictly on the auto-focus , what is the best method to start gaiing more clarity when trying to reach out 100-200 feet and bring the target close-up?..

Comments (16)

You might be better posting this question on the Canon 40D forum, especially if you think that this is a focussing issue..

Clearly cropping the image effectively enlarges it and therefore exagerates any defects. You could have a focussing problem, you could have motion blur or you could have a defective lens..

Do you get the same problem with shots of stationary subjects? If so, it could be a lens issue..

What are the typical shutter speeds of the shots that aren't crisp?.

(By the way, a Canon 70-200 f4 L lens is definitely not "basic"! If you have a 70-200 f2.8L it is even more non-basic!)Chris R..

Comment #1

Are you using a tripod & remote release or hand holding? if so, are you using a high enough shutter speed to prevent blur? are you actually focusing on your subject? what f no. are you using? what iso setting? do you sharpen your images in ps or other sofware?..

Comment #2

Sorry - I guess I left a few of the more critical details out, huh?.

The two lenses are:28-135 (f/3.5-5.6), and sorry, it's a 75-300 zoon (f/4-5.6) (the $200 one...).

Crsipness issues seem to be consistent with both lenses and become more noticeable as the zoom tightens in..

Typical shutter speeds are in the high hundredths, so I don't believe it's a motion blur. Some of the objects are relatively still, like a player standing on a base or waiting while at-bat. A few are of the kids running and the shutter speed does a terrific job of stopping the action, but it is defintiely not as crisp as I would like..

I'm usually shooting around f/5 and the iso is usually set around 200..

Photos are almost always in bright daylight. Understand I am still an -extreme- novice, so many of the settings are coincidental more than intentional ! Trying to get a feel for what works best in a given environment..

I have used a tripod and gone "commando". Never with a remote release....

I have read that aperature can impact this sort of thing, so was wondering if that may be something to consider. Or, is an f/4 or 2.8 (drool!) lens simply going to do better? Cannot afford the 2.8 right now, but trying to figure out where the shortcoming is. Me or the hardware, or both....

Thanks!..

Comment #3

You might need to stop down more. I shoot with a 135-400mm f/4.5-5.6, and it needs to be stopped down to f/11 @400mm to maintain the sharpness.Steve..

Comment #4

Photography is harder than you may think..

First of all, lenses usually are not at their best wide open, ort close to wide open..

Second of all, zoom lenses, except for the really expensive ones, atre not at their best wide open..

Third of all for a beginner using a 300mm lens on a 40D professonal grade camera, 1/1000 of a second makes sense. At a lower / longer shutter speed, beginners have rarely developed the breathing techniques, hand-holding techniques that yield sharp pictures..

For reasons that escape many, exepnsive digital cameras like the 40D usually require extra sharpening using some editing program, after the photos are taken..

What have you set the sharpness parameter range at? This can make a significant difference in sharpness?.

Fourth of all, have you bothered to even try a semi-scientific sharpness test? Put the camera on a tripod. SEt the shutter speed at 1/1000. Focus carefully on a subject that is genuinely sharp. (Trees with shimmering leaves in a breeze are not sharp. A painted baseball scoreboard is probably sharp. Set the lenses at apertures are a stop and a half, or farther, from wide open..

Take pictures, sharpen them in some software (I like Photoshop Elements 6) and make 11x14 prints. Are the pictures sharp now, or not?.

CHEAPIE HINT. you can, at many labs, blow up an image to a nice big size, and then just crop out 4x6 areas, so you can, for instance, get a 4x6 fromt he middle and a 4x6 from a corner, and see how sharp a bigger print would have been, for half a buck or less..

Changes are the problems with the 28-135 lens are you, and with the 70-300, it's the nature of the lens past about 250mm; still very good for a 4x6 or 5x7 print and not so good for a 16 x 24 print. Solving this proiblem is easy enough with enough money that's why Canon makes expensive telephoto lenses for people who want big prints, and the bargain lens, for people who only have a small budget and are happy with smaller prints..

BAK..

Comment #5

Just to add to the points made by others..

First of all, the 75-300 is one of Canon's poorer lenses. The 70-300 IS is much better optically and has IS (although this won't be much use for sports). The 70-200 f2.8 L and f4 L lens are outstanding..

Secondly, at 300mm you really need a shutter speed of at least 1/500 to avoid camera shake. With the 40D you can certainly put the ISO up to 400 without any noise, and even 800 will be pretty good..

Try the test on a tripod that BAK has suggested. Also, the next time you shoot sports, put the ISO on 400, set the camera to Aperture Priority Av, and adjust the aperture to give you a shutter speed of at least 1/500. See how this works. See whether smaller apertures (higher f numbers) give you better images. Try ISO 800 if necessary..

You may get better results if you have only the centre focus point selected. Most people find it easier like this. Also experiment a bit with continuous shutter mode - shoot bursts of 3-5 shots. Sometimes one of these shots will be much better than any of the others..

Don't use AI Focus - this can lead to focussing problems and it is generally not recommended. Leave the focus on single shot although you might want to experiment with AI Servo for moving subjects when you get more used to the camera.Chris R..

Comment #6

Thanks for the suggestions! I realize there is a lot to learn and strongly guessed the issue mainly resides in my technique (or lack-of)....

I presumed the 28-135 lens would be marginally better than the larger zoom, but in both cases, I have read many times that either end of the spectrum can be expected to have some fall-off, so thank you for confirming that..

As a starting point, what shutter and "f" would you suggest for the larger zoom?.

As an example, I'm generally zoomed somewhere in the 75% range at a max and am in strong daylight with little to no cloudcover. As I say, it's typically on a ball field... I've been trying to shoot btwn 1/500th and 1/1000th, iso at 200 and f/5.6. If I go up to the 11 range, will that make for a better potential? Higher the "f", (within reason) the better...? I do realize there are other contributing factors of course..

Also, I know there are more than a few books out there on the subject - any suggestions for a good "dummy-like" book?.

I wanted a good camera since I'm pretty sure I won't be buying another one any time soon. This seems to have been a good choice based on reviews, talking to others with more experience, etc.....

Comment #7

Book- "Understanding Exposure" by Bryan Petersen, one of the best. Or any basic photography book digital or film (just substitute film with sensor) should point you the right direction..

Test- BAK gave you guidelines that are good for a baseline. Tripod mount(negates shutter speed), fill the frame at the desired focal length with a detailed item and starting at the widest aperture, start snapping and stop down each shot..

Review each shot on your computer to see which one retains the most detail. That'll be the desired f/ stop at that focal length, so now all you do is adjust your ISO to get your desired shutter speed.Steve..

Comment #8

Awesome! I'll give all this a try and see what we come up with..

Thanks for the suggestions!..

Comment #9

Without seeign the images in questiona few folks are dancing around the problem a tad. You're using consumer zoom with the aperture wide open. Just stop down a little from the max apeture for a better result .

***********************************************Please visit my gallery at http://www.pbase.com/alfisti.

Pentax Lens examples at http://www.pbase.com/alfisti/images_by_lens.

Updated May '08..

Comment #10

I quickly found the 75-300 to be pretty awful..

I picked up a 70-300 and after using it for some time I gradually came to the conclusion that the 70-200 f/4 which was only a few dollars more expensive at the place I bought from, would have been a much better lens for the money... The 70-300 I had got pretty soft past 200mm, and mine at least had a weird problem of ghosting when shooting wide open with IS switched on - I lost a whole aerial photo shoot thanks to that problem...

Comment #11

Set the lens on manual focus. Switch the camera to live view. With the camera on a tripod, manually focus the lens using the 10x magnification and take some test shots. If the images still look this soft, you have a bad lens. If they look good manually focused, then you have a problem with autofocus which may be in the lens or the camera...

Comment #12

Okay, fast-forward about 8 hrs....

I'm home from work now and did some experimenting....

I set the camera on a tripod in full sun - it's about 95 out today....

I used the 28-135 lens and zoomed all the way in on a fixed street sign approx 100' away. I then set to AV and took a shot at each Ap setting from top to bottom. I then cropped it to about 50% which may be pushing things, but I really wanted to see the hard edges to compare the focus. It looks like the best setting in full daylight @ iso400 is around f8 with it cranked to 135mm. I believe it auto-set the shutter to 1/1000th at f8. At that point, I couldn't distinguish in a jpeg any difference btwn f8 and f9.

I then pulled it out to 28mm and did the same thing. I couldn't crop it quite as close obviously, but at 50% crop it looks like f9 works the best @ 1/640th..

I'll probably play with iso a little, but does this sound like where you would expect to shoot in broad daylight? I'm fairly certain that at least with the 28-135 lens, the issue is with me rather than a hardware problem..

I'll play with the 75-300 lens, but I pretty much figured it would be a lower quality picture. It's been a temporary "for-now" piece that will eventually be replaced with an f4 IS version. Just can't afford that right now....

In spite of it all... I -AM- learning!..

Comment #13

Sweet Spot Lenses.

Defraction Optimum Aperture.

Http://www.bobatkins.com/photography/technical/diffraction.html.

Lens Sweet spothttp://www.normankoren.com/Tutorials/MTF6.html#Sweet_spot.

F8 to F11 is generally the sharpest portion of the lens.

Bill,Jr'I kind of like the Earth, it's where I keep all my Stuff.'Website; http://www.pbase.com/wboth125 Lake Wylie, SC..

Comment #14

The 28-135 is a much better lens optically than the 75-300..

If you are getting the same problems with the 28-135 it is almost cetainly a technique problem rather than a lens problem.Chris R..

Comment #15

That is pretty much what you would expect, as I mentioned above. You need to stop down..

Dittoz wrote:.

Okay, fast-forward about 8 hrs....

I'm home from work now and did some experimenting....

I set the camera on a tripod in full sun - it's about 95 out today...I used the 28-135 lens and zoomed all the way in on a fixed streetsign approx 100' away. I then set to AV and took a shot at each Apsetting from top to bottom. I then cropped it to about 50% which maybe pushing things, but I really wanted to see the hard edges tocompare the focus. It looks like the best setting in full daylight @iso400 is around f8 with it cranked to 135mm. I believe it auto-setthe shutter to 1/1000th at f8. At that point, I couldn't distinguishin a jpeg any difference btwn f8 and f9.

I then pulled it out to 28mm and did the same thing. I couldn't cropit quite as close obviously, but at 50% crop it looks like f9 worksthe best @ 1/640th..

I'll probably play with iso a little, but does this sound like whereyou would expect to shoot in broad daylight? I'm fairly certain thatat least with the 28-135 lens, the issue is with me rather than ahardware problem..

I'll play with the 75-300 lens, but I pretty much figured it would bea lower quality picture. It's been a temporary "for-now" piece thatwill eventually be replaced with an f4 IS version. Just can't affordthat right now....

In spite of it all... I -AM- learning!.

***********************************************Please visit my gallery at http://www.pbase.com/alfisti.

Pentax Lens examples at http://www.pbase.com/alfisti/images_by_lens.

Updated May '08..

Comment #16

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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