Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Feb 6, 2014, 3:21 PM   #1
Senior Member
 
Marawder's Avatar
 
Join Date: Oct 2010
Location: Geneva, SWITZERLAND
Posts: 677
Default Radical Shift in Sharpness when changing Camera Position

Hello everyone,

In the past months I've noticed a strange phenomenon with my camera (A35).
I talked to some people (other amateurs) about it and they seem to think that it's only in my head. A very condescending reaction.

The thing is, anytime I shoot a scene with the camera setin a vertical position, the sharpness of the image is IMPROVEDcompared to the same scene shot with the camera held in the usual horizontal position.

Let me illustrate:



-------------------------------------------------------------------------------------------------------------


As you'd expect, I used a tripod while focusing manually and then locked the exposure.
At 100%, you can clearly spot the difference. The second vertical image has better sharpness.
This happens AT ALL APERTURES, no matter if I'm using AF or MF.
Also, this is not limited to only one lens, which makes me think the problem has something to do with the camera.

Does anybody have any idea what could be causing this?
Is it fixable, or should I just start looking for a new camera?

Thank you!

P.S: Trolls, flamers and skeptics, to whom disbelief is virtually a religion, and who would be tempted to tell me that I'm doing something wrong, abstain yourselves! I've looked through enough images like those above to know that it's not a product of my imagination. Something is obviously wrong.
__________________
Sony α
dSLR-A580
Minolta AF 35-70mm f/4
Sony DT 50mm f/1.8 SAM

Tamron SP AF 17-50mm f/2.8 XR Di-II LD
Tamron SP AF 70-300mm f/4-5.6 Di USD XLD
Marawder is offline   Reply With Quote
Sponsored Links
Old Feb 6, 2014, 4:12 PM   #2
Senior Member
 
Join Date: Jan 2011
Location: Australia, New South Wales central coast
Posts: 2,907
Default

G'day mate

in your PS you state "Something is obviously wrong. " ...... no it isn't
you have a special camera designed for portrait photography where it can display every hair and pimple on the subject's face

More seriously - I do think you have discovered something here that is very interesting. It may be tied up with the in-camera JPG processing, it may be a JPG computational bug but whatever is the reason, good on you for a) discovering it, and b) asking for 'intelligent' responses for which this might not be one of them

Phil
__________________
Has Fuji & Lumix superzoom cameras and loves their amazing capabilities
Spends 8-9 months each year travelling Australia
Recent images at http://www.flickr.com/photos/ozzie_traveller/sets/
Ozzie_Traveller is offline   Reply With Quote
Old Feb 6, 2014, 4:32 PM   #3
Senior Member
 
Marawder's Avatar
 
Join Date: Oct 2010
Location: Geneva, SWITZERLAND
Posts: 677
Default

Quote:
Originally Posted by Ozzie_Traveller View Post
More seriously - I do think you have discovered something here that is very interesting. It may be tied up with the in-camera JPG processing, it may be a JPG computational bug but whatever is the reason, good on you for a) discovering it, and b) asking for 'intelligent' responses for which this might not be one of them
Thank you Phil for taking the time to read my post, I appreciate it.

Your explanation is reasonable and makes perfect sense, but I forgot to mention that I always shoot in RAW. Thus, the problem cannot be with the Jpeg processing.

I looked all over the internet and only found this post on another forum with the same issue:
http://www.thephotoforum.com/forum/d...izontally.html

Not to offend anyone, but the responses he received were pretty idiotic.
__________________
Sony α
dSLR-A580
Minolta AF 35-70mm f/4
Sony DT 50mm f/1.8 SAM

Tamron SP AF 17-50mm f/2.8 XR Di-II LD
Tamron SP AF 70-300mm f/4-5.6 Di USD XLD
Marawder is offline   Reply With Quote
Old Feb 6, 2014, 6:41 PM   #4
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

I think it's possible that the image sensor shifts when you rotate the body. This might be the result of the additional freedom of movement that the sensor shift image stabilization provides, compounded by some failure of the camera to precisely position the image sensor.

I would be interested to know if the sharpness changes whether you rotate the camera in either direction. I'd also like to know if the sharpness changes whether the camera is tilted up or down. It will be difficult to construct a subject that would permit objective testing under those circumstances, but perhaps if you could attach a page from a newspaper to some backing material, and keep it well illuminated so as to maintain similar exposure settings while you tilted it up and down, that would eliminate other possibilities.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is online now   Reply With Quote
Old Feb 7, 2014, 7:23 AM   #5
Senior Member
 
Marawder's Avatar
 
Join Date: Oct 2010
Location: Geneva, SWITZERLAND
Posts: 677
Default

Good theory, Tom. Sounds plausible.

Quote:
Originally Posted by TCav View Post
if the sharpness changes whether you rotate the camera in either direction.
From what I've noticed, yes, any vertical direction offers a crisper image, no matter the aperture, no matter the focal length.

Quote:
Originally Posted by TCav View Post
I'd also like to know if the sharpness changes whether the camera is tilted up or down.
By tilted up and down, you mean the camera facing the ceiling, respectively the floor?
I'll try that too.

Made a test today in front of my outside wall.
Tripod, F/8, manual focus, exposure lock, 50mm...the difference in sharpness between horizontal and vertical shocks me everytime.
It's frustrating because it makes me whant to photograph everything in portrait orientation.



__________________
Sony α
dSLR-A580
Minolta AF 35-70mm f/4
Sony DT 50mm f/1.8 SAM

Tamron SP AF 17-50mm f/2.8 XR Di-II LD
Tamron SP AF 70-300mm f/4-5.6 Di USD XLD
Marawder is offline   Reply With Quote
Old Feb 7, 2014, 10:18 AM   #6
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

The images you post aren't very helpful to me because it's difficult for me to see the same detail rendered in the different photos.

It's really difficult to gauge the relative sharpness of different images unless they all have the same subject. That's why I suggested a sheet of newspaper on a backing board of some kind. And by tilting up and down, I was just suggesting about 45 up and 45 down. Keeping the image consistent for all those shots would be difficult unless you used something like a sheet of newsprint or a painting or other decorative wall hanging of some sort, something with a lot of detail. And to rule out other factors, the exposure settings should be as similar as possible for all the shots.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.

Last edited by TCav; Feb 7, 2014 at 10:20 AM.
TCav is online now   Reply With Quote
Old Feb 7, 2014, 5:03 PM   #7
Senior Member
 
Join Date: Sep 2011
Location: Bangor,North Wales
Posts: 3,741
Default

An intriguing phenomenon- and the only thing I'll add is that the comparison section of your test images is viewed through a different portion of the lens.
In other words,in portrait mode your top of the image is the left side of the lens when in landscape orientation- thus the bottle tops were not both in the "top" so to speak.

I am inclined to be suspicious of the stabilizer however- and maybe conduct a test with the IS off...?
SIMON40 is offline   Reply With Quote
Old Feb 7, 2014, 10:20 PM   #8
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,234
Default

In your first set of photos, the vertical shot of the bottle shows definite change in sharpness from top to bottom, with the lower part of the bottle being quite soft.
You really, as TCav mentions, need to take your pictures of a standardized target, and when you post crops, they should show the elements at the same size. Exif info would also be of assistance.
Just based on what you have posted here, I would also suspect the anti-shake system. (Even when turned off, it could allow some sensor motion)

brian
VTphotog is online now   Reply With Quote
Old Feb 8, 2014, 8:05 AM   #9
Senior Member
 
Marawder's Avatar
 
Join Date: Oct 2010
Location: Geneva, SWITZERLAND
Posts: 677
Default

Quote:
Originally Posted by TCav View Post
The images you post aren't very helpful to me because it's difficult for me to see the same detail rendered in the different photos.
But it's the same portion of the wall!
After adjusting exposure and focus, I took the first horizontal shot, and then for the second shot I simply rotated my camera into the vertical position with the help of the tripod head. No fuss at all.

Both crops are 1:1.

Why are you asking me to take more test-shots since you already acknowledged the problem exists?

Quote:
Originally Posted by TCav View Post
And to rule out other factors, the exposure settings should be as similar as possible for all the shots.
Did it seem to you to you like the exposure settings where not the same? They were in fact identical.

Quote:
Originally Posted by SIMON40 View Post
I am inclined to be suspicious of the stabilizer however- and maybe conduct a test with the IS off...?
The camera was always on a tripod, thus with IS turned off.

Anyway, I plan on contacting the local Sony shop. It would be ridiculous if they didn't have any idea of what the cause of this might be.
__________________
Sony α
dSLR-A580
Minolta AF 35-70mm f/4
Sony DT 50mm f/1.8 SAM

Tamron SP AF 17-50mm f/2.8 XR Di-II LD
Tamron SP AF 70-300mm f/4-5.6 Di USD XLD
Marawder is offline   Reply With Quote
Old Feb 8, 2014, 5:40 PM   #10
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Quote:
Originally Posted by Marawder View Post
But it's the same portion of the wall!
After adjusting exposure and focus, I took the first horizontal shot, and then for the second shot I simply rotated my camera into the vertical position with the help of the tripod head. No fuss at all.

Both crops are 1:1.

Why are you asking me to take more test-shots since you already acknowledged the problem exists?
I haven't acknowledged that the problem exists. I've just suggested a possible cause for the problem you're seeing. I don't see the problem based on the images you posted, and I've suggested some alternative shots that would more clearly show the problem you describe.

Quote:
Originally Posted by Marawder View Post
Did it seem to you to you like the exposure settings where not the same? They were in fact identical.
That's good to know, but the images you posted don't have any EXIF data, so that info was not available, and changes in the aperture or shutter speed could also have caused a change in sharpness.

Quote:
Originally Posted by Marawder View Post
The camera was always on a tripod, thus with IS turned off.
IS being on or off isn't the issue; the issue is whether or not the sensor is at the exact same distance from the lens as the orientation of the camera body changes. If the sensor was allowed to shift front-to-back because the IS mechanism wasn't properly positioning the sensor front-to-back wouldn't have anything to do with whether IS was on or off.

Quote:
Originally Posted by Marawder View Post
Anyway, I plan on contacting the local Sony shop. It would be ridiculous if they didn't have any idea of what the cause of this might be.
Good idea.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is online now   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 10:37 AM.