Soft images

siberia1997 · Mar 29, 2005

I'm new to digital, so please bare with me. I have a 20D. When I shoot with my Tamron 70-300 (f4/f5.6), and I zoom long to 300 mm or near 300 mm, with autofocus on, the images that I download and view in Photoshop Elements seem a little on the soft side when viewed at 100%, even where my focus point was when I took the shot. At 70 mm or 135 mm (+/-), things look a little crisper. The same is true with my Sigma 170-500 (f5/f5.6). The Sigma images that I'm thinking of were taken at 1/1600 on a sunny day, without a tripod, but supported by a fence. The Tamron images were taken from a tripod and a remote switch. I took the shots in large JPG format on the 20D. I don't know much about Photoshop, but the instructor in a class I'm taking told us that with a large format JPG on a 20D (or other cameral with 8+ megapixels), we can print images up to 16" X 20". If I were to print the images that I referred to at that size, would I see some of the softness that I mentioned? Is the depth of field just so small at those focal lengths that I'm missing it? Or is it a limitation of the lens? Is it both? Am I expecting too much from the lenses to be able to print something that large at that focal length? Don't get me wrong, the softness at 100% at those focal lengths doesn't seem to be unacceptable, it's just that I know things can look sharper because I've seen images shot under the same lighting conditions, but at a smaller focal length. Would I even notice the slight softness that I do at 100% on the long focal length shots when I print at a more reasonable size, say 8X10 or 5X7? I'd experiment, but I don't have a photo printer yet.

Sorry to be so much trouble.

Thanks for the help.

Big Mike · Mar 29, 2005

Welcome to the forum.

I'm guessing that it's the lenses that you are using. Most consumer level zoom lenses are soft when fully extended. What aperture where the shots taken at? Most lenses have a sweet spot that starts a few stops from fully open.

You should be able to make nice 16x20 prints from the files taken with a 20D. Most people will recommend that you shoot in RAW mode rather than large JPG...it gives you more flexibility when editing.

Learn to use Photoshop. USM (Unsharp mask filter) will be one of your best friends.

siberia1997 · Mar 29, 2005

On the Tamron, I was shooting at 5.6 (I think) at 300 mm, which is wide open at that focal length. (I think it only shuts down to f4.0 at 70 mm, which gets back to the consumer-grade issue that you raised.) On the Sigma, I was shooting at 5.6 at 500 mm.

I'll try that trick in Photoshop. Does Elements include that, or will I need CS?

Am I being overly critical? Do you think I'll notice the softness on a large print (say, 8x12 or 16x20) that I see on a computer screen. It's not really bad on the computer at all. It's just that when you have something else to compare it to (i.e., the same subject, same lens, but shorter focal length), you wish that you could have the same sharpness, or wonder if you're doing something wrong. With the 20D and an autofocus lens, the camera won't let you shoot unless something is in focus. I know that I've seen one or more of the red lights for the focusing points illuminate on every shot that I've taken.

Digital Matt · Mar 29, 2005

While your dof is fairly shallow at long focal lengths, and that "could" possibly be a reason, I think most likely, the reason is that you are using consumer lenses, and what you are getting is as sharp as it gets.

At 5x7 or 8x10, you will certainly not notice the lack of sharpness as much, but you will notice it. At 16x20 you will definitely notice.

I can't say for sure without seeing though. If you posted a 100% as an example, it would help.

ksmattfish · Mar 29, 2005

siberia1997 said:
With the 20D and an autofocus lens, the camera won't let you shoot unless something is in focus. I know that I've seen one or more of the red lights for the focusing points illuminate on every shot that I've taken.

Are you sure you are focusing on the right spot? If you want a person's eyes to be in focus, but the AF point on their ear lights up, then the eyes might be soft.

Also, wasn't there an issue with the focusing on some of Canon's DSLRs? I think it's been mostly taken care of by now, but maybe you got one of those?