Sharpness Issues

[Cpalmer03]

I was wondering if anyone would be able to help out with some recommendations on why some of my shots are very soft, almost to where I am completely disappointed. I am at a loss whether it is my camera or lens or user error. Would love if someone could point out what I am doing wrong. I even fired a flash on this shot to ensure sharpness, and did not get what i was looking for. (Zoom to 100%)

Canon Rebel XTi
Kit 18-55 lens
ISO 100, f5.6, 1/125, 24mm
Aperture program says focal point is on the front of the jaw, as you can see, edges of teeth are so blurry and title underneath.

Thanks for the help! :hail:

 

[Buckster]

What was your distance to subject?

 

[Cpalmer03]

What was your distance to subject?

Dont know the exact distance. At 24mm focal length I was pretty close.

 

[Buckster]

What was your distance to subject?

Dont know the exact distance. At 24mm focal length I was pretty close.

Let's say 1 foot away. In that case, at 24mm, on that camera, per DOF calculations, you had about .6 inches (about half an inch) of acceptable sharpness depth from your focus point to the front, then it starts to blur fast, and another .72 inches of acceptable sharpness from your focus point to the rear, then it starts to blur fast. Your total was about 1.32 inches of acceptable sharpness to work in. Everything outside that zone is going to be blurry.

To get a wider area of acceptable sharpness, stop down your aperture more. f/16 would have given you about 3.6 inches. f/22 gives you a little over 5 inches.

Want more? Back up. You can always crop it a bit in post production.

From 2 feet away, f/5.6 gives you the same as that last one: a little over 5 inches. f/16 gives you almost 16 and a half inches.

Bottom line: Learn your DOF. This can help: Online Depth of Field Calculator

 

[bratkinson]

+1 to what Buckster said.

I think depth of field and shutter speed to stop movement are probably the two biggest issues those new to photgraphy run into. I know I trashed a bunch of blurry people pictures after a 15 year hiatus from photography and I jumped into digital. It took a while, but this old dog DID learn some new tricks...like DOF and shutter speed limitations/rules...and when to hold 'em, and when to support 'em on a monopod or tripod, Av, Tv, re-learn M, Photoshop, Lightroom...kick the computer...

 

[TCampbell]

And to complicate things... suppose you're using the default "One Shot" focus mode (as opposed to "AI Servo") and you've got that narrow DoF of less than an inch. In that mode, the camera only focuses once per shot... it'll focus and lock. If your body sways even a tiny bit then you've just moved the focus distance ahead or behind your subject (and you can move this much without even realizing it.) Macro / close-up photography classically has this problem. Basically anybody who wants to buy a macro lens should probably buy a tripod first.

 

[amolitor]

That's a T-Rex jawbone. He's more than 1 foot away, more like 5-8 feet. I don't think this is entirely a DoF issue.

The lens appears to be producing a fair bit of chromatic aberration (I think. There's ugly fringing along the sign's lettering, anyways) and quite a low contrast image which is interfering with acutance in a big way.

 

[Buckster]

That's a T-Rex jawbone. He's more than 1 foot away, more like 5-8 feet.

24mm

 

[amolitor]

24mm on a crop sensor, with a field of view about 8 feet wide gives you a working distance of about 8 feet, which is about what I am estimating his field of view (at the plane of what we might jokingly call "focus" with the thing he has on the front of his camera).

T-Rex jaws are pretty large objects. It could easily be 4 feet from the first tooth to the second. The sign suggests the animal this came from was 47' feet long, and the damned things were all mouth.

 

[invisible]

Even though this was shot at 1/125 with a 24mm lens, the lack of sharpness in this photo looks like camera shake to me. Here's one of many articles out there that might help you control camera shake: 5 Tips on How to Hold Your Camera

 

[Buckster]

Even though this was shot at 1/125 with a 24mm lens, the lack of sharpness in this photo looks like camera shake to me. Here's one of many articles out there that might help you control camera shake: 5 Tips on How to Hold Your Camera

Why isn't the whole thing as blurry as the sign underneath then?

 

[christop]

It just looks out of focus to me. The blur is too round and consistent to be camera shake (and the bone itself looks to be illuminated almost entirely by flash which is too fast for a little camera shake).

If the lighting was dim, the lens may have had a hard time focusing on any part of the bone. In those cases you can use the flash's AF Assist to provide more light for the auto-focus mechanism.

 

[Buckster]

24mm on a crop sensor, with a field of view about 8 feet wide gives you a working distance of about 8 feet, which is about what I am estimating his field of view (at the plane of what we might jokingly call "focus" with the thing he has on the front of his camera).

T-Rex jaws are pretty large objects. It could easily be 4 feet from the first tooth to the second. The sign suggests the animal this came from was 47' feet long, and the damned things were all mouth.

That's still only 38mm, which is wide enough. I guess we'll have to rely on OP to tell us how far away he actually was. When he said, "24mm... pretty close", I took it to mean just that. Meanwhile, feel free to speculate whatever you like.

 

[invisible]

Even though this was shot at 1/125 with a 24mm lens, the lack of sharpness in this photo looks like camera shake to me. Here's one of many articles out there that might help you control camera shake: 5 Tips on How to Hold Your Camera

Why isn't the whole thing as blurry as the sign underneath then?

I never said that my observation skills were good The thing and the sign both look blurry. The window behind them on the other hand doesn't, so you make a good point. Not camera shake.

 

[amolitor]

It isn't REALLY all that unsharp. Hit it with some more contrast and a little unsharp mask and it peps right up. This feels like a bunch of contrast reducing crap on the front of the camera, to me.

OP, are you by any chance using a "protective UV filter" on the front of your lens, and have you tried removing it?