Soft pictures when shooting distant subjects

Hello.

I'm really sick of this. My 30D with the 18-55 took good shots indoors, but outside it sucked most of the time. It was just as it didn't find correct focus. Distant subjects were most of the time blurred, no matter the lightning, tripod or no tripod etc.

Yesterday I bought the nifty 2 fifty (55-250 IS). It seemed a great lens as I fooled around indoors (and most importantly, it was razor sharp). Remembering my old 18-55 problems, I did the battery tests to check focus accuracy. No back or front focus found, actually the focus seemed excellent.

This morning I shot some buildings in the distance. They were blurred at 55mm F4. I stopped down the lens to F5.6-F7.1 and sharpness increased. Remember that at small distances the lens is sharp, even wide open.

Now...Please don't tell me that this is normal and the lens resolves great distances to infinity. And don't advise me to buy an L or something. My girlfriend has a Nikon D40. That little camera takes shots 10 times better than my "semi-pro" 30D. None of her lenses (18-55 and 55-200 VR) have this problem with distant subjects. I shot the same scene with that D40+55-200 VR at 55mm F4 and it was tons better than my shot.

I hate this friggin' camera and I'm starting to hate all Canon. Why does this happen? I'm losing my mind here I can't believe that I paid maybe 3 times the money for something that takes worse pictures than that D40!! I've always been a Canon supporter but I'm sick of this!

PS: Oh and that 55-200 VR doesn't have a rotating front element, focusing is done inside the lens, it's smaller and it's half the price. If you want I'll post some 100% crops tomorrow...

No one will be able to help out much without a picture or two.

Just how distant? Eventually atmospheric effects will come into play.

Yeah, I thought this will be the case...Unfortunately I don't have those pictures anymore so I'll upload them tomorrow. I just wanted to know if this is "normal" behavior because it seems I'm not the only one with this problem (some guys from the 55-250 topic have this issue as well).

Anyway, it couldn't be normal because that D40 doesn't behave this way.

@Stregone: about 300 meters. I'm not talking about huge distances and anyway it must be a problem with my camera because the D40 takes a sharper picture in exactly the same conditions.

Again, I'm sorry that I can't post any pictures now. It would've been better if I would have posted this tomorrow, along with the crops but I was just too nervous.

Seems that you’ve already set your mind on Nikon.
We can try to explain the importance of Depth of Field, but it might not convince you.
In that case, just sell 30D, buy D40 and be done with it.

Hermeto please don't start this. I know what DOF is.

And I think you don't understand something: Nikons have larger sensors than Canon. Their crop factor is 1.5, while Canon has 1.6. The larger the sensor, the smaller the DOF, right? So pictures taken with the camera with the smaller sensor should appear sharper sometimes because focus accuracy is less of an issue.

Now...if the D40, with a smaller DOF, takes a sharper photo than my camera that has a larger DOF, it means that my camera must have a problem, right? It seems pretty logical to me. The 30D has a supposedly much better AF module than the Nikon D40.

Considering the above-mentioned facts (especially the one about crop factors), isn't it suspicious? If the 1.5 crop factor camera would take the blurred shot, I would have said that it's normal, because its DOF is narrower. But my 30D has a larger DOF and a better AF module.

Now...If I got anything wrong, please correct me.

EDIT: I don't have my mind set on Nikon. Quite the opposite. I hate the fact that my Canon has a problem and the lowest end Nikon outperforms it. I just want to get to the bottom of this so don't throw that kind of stuff at me.

Already stated, you're asking for help/diagnosis of a potential problem but there are no images to compare. So be patient, retake example shots between your 30D and your g/f's D40 and post them up. Yes, you may have a crappy 30D, or you may not. But none of us can tell you one way or another without seeing side-by-side comparisons.

Are you shooting RAW? Are you shooting jpg? Does Nikon do more in-camera sharpening by default? There are a lot of variables, INCLUDING the possibility that your 30D just suck. But again, w/o photos, you're just grasping at straws here. Post them up. Want our thoughts? Then give us more info to work with.

not_this_punk wrote in post #7177832
Hermeto please don't start this. I know what DOF is.

And I think you don't understand something: Nikons have larger sensors than Canon. Their crop factor is 1.5, while Canon has 1.6. The larger the sensor, the smaller the DOF, right? So pictures taken with the camera with the smaller sensor should appear sharper sometimes because focus accuracy is less of an issue.

Actually, you aren't understanding this correctly. A larger sensor only has less DoF because (to get an identically framed image) you need to use a longer lens. It is the difference in focal length that changes the DoF, not the size of the sensor.

In fact, a larger sensor has greater DoF (when FL is unchanged) as the image needs to be enlarged less.

As you say you took both shots at 55mm, then the Nikon should actually exhibit slightly better DoF. Although the difference is unlikely to be the cause at this sort of range as DoF from a 55m at 300m range is pretty wide.

Nikons generally seem to have higher sharpening, saturation etc. levels by default, when compared to Canons. This sometimes makes them seem to produce images with more 'pop'. This may simply be a case of how the cameras ae set up, perhaps bumping the sharpening up a little on your 30D may give similar results.

I'm only guessing there of course, without knowing more about how you are taking the shots / seeing examples, it is hard to take anything more than a wild stab in the dark.

not_this_punk wrote in post #7177832
Hermeto please don't start this. I know what DOF is.

And I think you don't understand something: Nikons have larger sensors than Canon. Their crop factor is 1.5, while Canon has 1.6. The larger the sensor, the smaller the DOF, right? So pictures taken with the camera with the smaller sensor should appear sharper sometimes because focus accuracy is less of an issue.

Now...if the D40, with a smaller DOF, takes a sharper photo than my camera that has a larger DOF, it means that my camera must have a problem, right? It seems pretty logical to me. The 30D has a supposedly much better AF module than the Nikon D40.

Considering the above-mentioned facts (especially the one about crop factors), isn't it suspicious? If the 1.5 crop factor camera would take the blurred shot, I would have said that it's normal, because its DOF is narrower. But my 30D has a larger DOF and a better AF module.

Now...If I got anything wrong, please correct me.

EDIT: I don't have my mind set on Nikon. Quite the opposite. I hate the fact that my Canon has a problem and the lowest end Nikon outperforms it. I just want to get to the bottom of this so don't throw that kind of stuff at me.

Wrong.
Everything else being equal, larger sensor produces larger DoF.
But you are right; let’s see the pictures and we’ll have an idea.

I am still willing to bet that the problem you described has to do with the DoF and perhaps, with the lens.
Sensor size has nothing to do with it.

Forget DoF right now.
He's talking 55mm F4.0 at 300m. Depth at this point is not really a concern. Large sensor, small sensor, doesn't matter so lets just step away from the side tracking.

Yes you are absolutely right. I'll take the test shots again tomorrow and post them up. But just for the sake of it, I tried bumping up the in camera sharpening (almost to the maximum).

Anyway the camera is still in warranty so I could take it to Canon. My main concern was that they'll tell me that this is normal, that the lens has a "maximum focus distance" before it sets itself to infinity. I now understand from your replies that this is not normal so I'll give Canon a call on Monday.

I'll post the test shots tomorrow after I take them.

Many thanks for all your replies thus far. This forum is the best

Hermeto wrote in post #7177892
Wrong.
Everything else being equal, larger sensor produces larger DoF.
But you are right; let’s see the pictures and we’ll have an idea.

I am still willing to bet that the problem you described has to do with the DoF and perhaps, with the lens.
Sensor size has nothing to do with it.

I think you've got this backwards. A 30D will have more "apparent" DoF than a 5D will, so a larger sensor gives you less "apparent" than you will get with a smaller sensor. Therefore, technically a D40 with a larger 1.5 crop sensor will give you slightly less DoF than a 30D with a 1.6 crop sensor. Although no human will really notice this difference.

As for the OP's problems, there is no way anyone can really have any idea what is causing these problems without seeing example images.

If you deleted the images, you can use the free version of Zero-Assumption Recovery to recover the images and post them for review.

300meters is about 1000ft (1/4 of a mile). Just a tiny bit of shake will make the image blurry EVEN with tripod. Like others said...without any photos...with exif intact. We can not do much. Great light outdoors not mean great photos. Like others mention. The elements play a great deal...fog, dust, wind.

Try this "simple" test. Put your 30D on the tripod with the lens in question. Use the longest focal length and AF on the subject. Now while keeping you eye on the viewfinder. Just barely and I mean barely tap the camera....it will seem like an earthquake in the viewfinder. This is where a remote cable comes into play.

Thanks for the explanation about DoF sandpiper and Hermeto. I would have never thought that the focal length is all that matters in DoF but...it's very logical. Now that I think of it I don't see what influence sensor size could have on DoF. Thanks for the heads-up anyway