Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: jaisfoto on October 02, 2011, 03:58:01 pm
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Hello,
I found recently a cfv-39 in a excellent condition and did test shots with a 503CW kit (80cfe&120cfi).
but, the result was quite disappointing because the focusing was slightly missed from the intended focusing points.
the worse is that even the points focused look little bit soft. Not being sure if these problems come from digital back or camera&lens, i tried to focus on infinity. the result was still worse. there're nothing of sharp.
is there someone who has the same experience ?
do i have to check the 503cw&lenses in first ? or what should i do ?
Thank you for your opinion in advance
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My guess would be that the body/mirror is out of alignment, the 39 is a good back and when focussed should certainly not be soft. I would set up the camera tethered and focus on a ruler running away from camera then see where the actual focus ends up. If focus is consistently off with the two lenses then that suggests that the body/mirror needs a service.
Nick-T
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Thank you Nick T,
i'll try as you advised.
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I had the same with my 500 c/m and CFV-39. I let them adjust at Hasselblad's, works perfectly now.
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Soft focus is usually camera/lense related. I have yet to see a "Back" which is soft focus! As the sensor chip is a semiconductor, it is absolutely flat on its surface, nor can any curvature creep into the process, hence centre or edge "out-of-focus" conditions never occur.
With the camera body and lense it is a different story.
. The body can off registration with the mirror
. The body can have off registration with the back
The best DIY that I have tried, is to get some thing like a "Lense Align" focus at the centre and find where the focus is on the back. Then adjust the focusing screen to synchronize with the back. An incline steel/wooden scale marked set up at an incline (towards and away from you), will also do admirably in this case.
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Soft focus is usually camera/lense related. I have yet to see a "Back" which is soft focus! As the sensor chip is a semiconductor, it is absolutely flat on its surface, nor can any curvature creep into the process, hence centre or edge "out-of-focus" conditions never occur.
In many cases it is true. But I disagree that there is no problem "out-of-focus" for example on one edge. I have seen such cases, when equipment fell. That's my 2 cents.
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Roy,
It happens more than you can imagine, a sensor being out of alignment. Sometimes it can be too far, some other times too close to the optimal sharpness plane. But it happens as well that the sensor is inclined, with the edge of the image out of focus.
That's why Alpa cameras (back adapters) have the possibility to shim the sensor/back, either bring it closer to or further away from the lens, or it is even possible to shim only for the edge, on one side:
Alpa adjustable back adapter (http://www.alpa.ch/en/products/backs-adapters/digital-backs-and-adapters/alpa-adjustable-back-adapter-haa.html)
Thierry
Soft focus is usually camera/lense related. I have yet to see a "Back" which is soft focus! As the sensor chip is a semiconductor, it is absolutely flat on its surface, nor can any curvature creep into the process, hence centre or edge "out-of-focus" conditions never occur.
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Wow...i really appreciate you for your attention.
Today, i've heard that it would cost 400-600 € for checking the camera (alignment & overall cheking) in Paris.
And if i have to modify my PME90 to use with cfv 39, 150€'ll be added.... i think that it'd be better waiting for the test result from the seller.
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Hi,
You could try "lens align", or do some simple focus for front or back focus. It would also be helpful if you posted some actual pixels crops of an image which shows the problem.
Best regards
Erik
Wow...i really appreciate you for your attention.
Today, i've heard that it would cost 400-600 € for checking the camera (alignment & overall cheking) in Paris.
And if i have to modify my PME90 to use with cfv 39, 150€'ll be added.... i think that it'd be better waiting for the test result from the seller.
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Yes the sensor may be out of alignment
. It can be too far or too near
. It can be tilted
But it can never be warped. Nor can you get the type of soft focusing that happens due to lense problems.
Any way getting the camera adjusted should solve the problem. Otherwise the back has to be adjusted in the factory.
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True, of course.
Thierry
But it can never be warped. Nor can you get the type of soft focusing that happens due to lense problems.
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Hi,
I'd suggest that you make a series of simple tests.
1) Take a picture of a brick wall or similar at 45 degrees angle. Try to find a part of the wall that is in focus. Is that the part you have focused on?
2) Shoot the brick wall at 90 degree angle. Are corner equally sharp/unsharp?
3) Try a focus bracket, shoot several shots at different focusing distances
These tests would give a decent idea about alignment problems.
Best regards
Erik
True, of course.
Thierry
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Unfortunately, i don't have the cfv39 with me for the moment. so i can not test as eric advised.
and i've got a phone call about the test result from seller. he said there's no problem with another camera.
i'll test as you taught me when i receive the back.
thanks x 100000000000000000000