Something wrong with my 60D?

[Fastchas]

I'd be grateful if someone could help me on this?
I've been a little disappointed with the image quality on my canon 60d. I bought it as a replacement to my 20d which I still have. I've set up the tripod and used a canon 50mm, swapping it over. I've took a shot of a metal tape measure, centre point focussing on the number '20'.
After zooming in quite a lot I can see the 20d photo appears sharper than the 60d (which is the lighter one). All taken at the same settings (Iso, aperture, shutter).
Is this the correct way to judge the quality and would you agree of my opinion? Would you send the camera in to be looked at?
Thanks chaps (and chapesses)

20D

60D

[Disastrous]

What type of picture format are you shooting? RAW, JPEG, what quality etc?

Not sure why but those two crops aren't showing as the same size on here so my suspicion is you might not be comparing apples with apples...(unintentionally, I mean).

ETA - would that just be the higher pixel count??

Beyond that, I'm not sure off the top of my head. I've got a 60D but don't know the 20D at all...

ETA - are they being taken from the same distance? It's not just out of focus is it??

Edited by Disastrous on Friday 15th April 00:44

[Fastchas]

Thanks for your comments.
The distance between the tripod fixing mount and the tape measure hasn't changed, the difference in crop size is my hamfistedness. I get what you're saying about them being slightly incomparable but it's the best I could do. It really is zoomed in about 300%.

[Disastrous]

Fastchas said:

Thanks for your comments.
The distance between the tripod fixing mount and the tape measure hasn't changed, the difference in crop size is my hamfistedness. I get what you're saying about them being slightly incomparable but it's the best I could do. It really is zoomed in about 300%.

Thanks - I've been trying to think more on this overnight.

What were the picture settings again? I wondered if the 60D was set to RAW and needing a touch of sharpening?

Beyond that, it actually looks slightly as if the image is coming closer to focus as you get closer to the camera so could it just be an incorrect point of focus (though I know you said you used the center point on each)...?

[Fastchas]

Both camera's set to high res JPEG, centre point, tripod, F1.8 on a canon 50mm, both at 1/20 or 1/30 sec (I'm not at home to check), and both at ISO400.
Would you be able to suggest another way to test that I could do?

[Disastrous]

Fastchas said:

Both camera's set to high res JPEG, centre point, tripod, F1.8 on a canon 50mm, both at 1/20 or 1/30 sec (I'm not at home to check), and both at ISO400.
Would you be able to suggest another way to test that I could do?

Hmm, interesting.

I would think there are probably far more expert posters than me on this sort of subject (I think I am better at taking photos than knowing how cameras work) who might be able to suggest better test benchmarks but my suggestion might be to go for a faster shutter speed (I know you're on a tripod but could you be introducing a touch of camera shake? Are you using a timed shutter release?) and maybe a more mid-range aperture as IIRC the Canon 50mm (I'm presuming it's the 1.8 rather than the 1.4 set to 1.8) can often get a bit soft wide open (prepared to be corrected on that!).

Also, I don't use JPEG but perhaps the different models process the RAW data differently, and apply varying amounts of sharpening to the image?

I would definitely shoot in RAW to test I think, as then I know the camera isn't introducing any unknowns...

PS - I'm also assuming you aren't in any creative modes on either camera that might be introducing any image processing?

If you let me know what distance you are shooting at, I can try a comparison shot on mine and see if it looks the same?

[Fastchas]

Good stuff.
It is the F1.8, wide open. I thought it might only be soft at the edges though?
Interestingly, I have a remote trigger for my 60D which I used but it doesn't fit the 20D so I had to depress the button for that! If the photo's were the other way around then I would expect that (they're not, I checked).
Both shot in manual.
I'll do some more tonight, maybe try a better comparison. I'll also try the EF-S 18-135mm I have? Would it be better around 50mm and cropped or at full length and cropped? I think the difference is size of the pics could be the difference in the front-to-back thickness between the 20d & the 60d. Maybe the lens is closer to the subject on one than the other which is magnified when cropped?

[Disastrous]

Fastchas said:

Good stuff.
It is the F1.8, wide open. I thought it might only be soft at the edges though?
Interestingly, I have a remote trigger for my 60D which I used but it doesn't fit the 20D so I had to depress the button for that! If the photo's were the other way around then I would expect that (they're not, I checked).
Both shot in manual.
I'll do some more tonight, maybe try a better comparison. I'll also try the EF-S 18-135mm I have? Would it be better around 50mm and cropped or at full length and cropped? I think the difference is size of the pics could be the difference in the front-to-back thickness between the 20d & the 60d. Maybe the lens is closer to the subject on one than the other which is magnified when cropped?

I've no idea about the 18-135 I'm afraid - never had one...

Ah well, at least you can probably discount the camera shake thing - always good to eliminate stuff from the enquiries.

I think I'm starting to run out of ideas but when you are measuring the distance to the subject, are you using the marker on the camera body rather than the front of the lens?

It's just occurred that at such a wide aperture, if you are close to the minimum focal length of the lens, your depth of field could be shallow enough that it's making the difference. It might also explain why the 60D image looks sharper, closer to the camera.

Probably a long shot but just a thought!

[dogbucket]

I would try live view to focus (contrast AF) which would eliminate any front or back focusing issues with the phase AF. To start with use something face on to the camera like a bank note or similar with live view to confirm the camera is ok. Stop it down abit to F4 or more to maximise lens sharpness. Then you can use an angled target like the tape measure with the lens at 1.8 to investigate front or back focus. If the camera has AF fine tune use that to get the focus plane to match were the AF was targeted.

I have found large aperture primes always need a tweak.

Edited by dogbucket on Friday 15th April 12:04

[Fubles]

Just FYI on the top right of the viewfinder on the 60d is a little white circle with a line through it, the line represents the placement of the sensor within the camera, there'll be one on the 20d somewhere also, so this is what you should use as a datum for your shots

[Disastrous]

Fubles said:

Just FYI on the top right of the viewfinder on the 60d is a little white circle with a line through it, the line represents the placement of the sensor within the camera, there'll be one on the 20d somewhere also, so this is what you should use as a datum for your shots

Yeah - that's the thing I mean, on the top of the camera body.

I wonder if they have different thicknesses and the OP has measured from the front of the lens?

[Fastchas]

I was not aware of this. It's too late now to set up but from what I now understand I'm guessing the datum line in what I need to measure the distance from the subject rather than the front of the lens?

[Disastrous]

Fastchas said:

I was not aware of this. It's too late now to set up but from what I now understand I'm guessing the datum line in what I need to measure the distance from the subject rather than the front of the lens?

Exactly. This is the thing to look for:



Not sure how different this will be between 20 and 60d but if you're fo using very close, it might be enough to make the difference, especially wide open...

[Fastchas]

Thanks for that, I'll get on it over the weekend. In the meantime, I've updated the firmware tonight, it was out of date. Dunno if that will have any effect?

[Simpo Two]

If you're using autofucus does it matter what the distance is? Surely what actually matters is whether the camera focuses correctly on the spot you point it at. I think the film plane line is a red herring.

[Disastrous]

[quote=Simpo Two]If you're using autofucus does it matter what the distance is? Surely what actually matters is whether the camera focuses correctly on the spot you point it at. I think the film plane line is a red herring.[/quote


It matters if it's closer than minimum focus distance though, right?

[Fastchas]

The '20' on the tape measure was way further than minimum distance. It focused on the '10' which was obviously 10cm nearer.

[Disastrous]

Fastchas said:

The '20' on the tape measure was way further than minimum distance. It focused on the '10' which was obviously 10cm nearer.

Are you meaning the tape measure is actually representing the distance from the lens?

I'd not understood that if so - I though you had just picked something to focus on.

I'm not sure what the minimum focal length for that lens is off the top of my head so not sure if it could be an issue or not.

I suppose it's possible the AF is just broken!

[Fastchas]

No it's not 20cm from the camera. The beginning of the measure might be a good 4/5" from the lens.

[Simpo Two]

Disastrous said:

Simpo Two said:

If you're using autofucus does it matter what the distance is? Surely what actually matters is whether the camera focuses correctly on the spot you point it at. I think the film plane line is a red herring.

It matters if it's closer than minimum focus distance though, right?

Forget it's a tape measure, it's not measuring anything, merely a sloping thing with things on it.