Lens calibration - Focus Tune software
Posted 28/04/2013 - 20:51
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IMO this software is a complete waste of money and time.
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Posted 28/04/2013 - 20:56
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Mannesty wrote:
This all makes me think the the sooner all DSLR's go mirrorless, the better.
Surely the inaccuracy of the actual point of focus is down to the mechanical tolerances of the mirror adjustment and placement of the focus sensors.
So with no mirror and the focusing being done by the image sensor should eliminate some of these issues.
It eliminates ALL of these issues. The problem is the speed of focus. The Contrast method of focussing through the sensor is a lot slower than the phase method of using dual lenses and a seperate AF sensor.This all makes me think the the sooner all DSLR's go mirrorless, the better.
Surely the inaccuracy of the actual point of focus is down to the mechanical tolerances of the mirror adjustment and placement of the focus sensors.
So with no mirror and the focusing being done by the image sensor should eliminate some of these issues.
http://graphics.stanford.edu/courses/cs178/applets/autofocusPD.html
versus
http://graphics.stanford.edu/courses/cs178/applets/autofocusCD.html
Anyway you can use the contrast method of focussing in Pentax DSLRS now. It's there as an option
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Posted 28/04/2013 - 22:27
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JAK wrote:
Is the software camera specific?
No, but some Canon and Nikon cameras output their adjustment settings, Pentax doesn't, which means you can only use the shot by shot comparison analysis method.Is the software camera specific?
It does produce interesting results though.
I spent some time testing/adjusting some of my lenses today and the adjustments required vary from +2 for my DA* 50-135mm to -8 for my Sigma 150-500mm lenses.
I just need some decent daylight time now to test the adjustments that this software is suggesting.
Peter E Smith - flickr Photostream
Posted 28/04/2013 - 22:37
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Mannesty wrote:
No, but some Canon and Nikon cameras output their adjustment settings, Pentax doesn't, which means you can only use the shot by shot comparison analysis method.
It does sound like a lot of work. Well I won't be trying it but don't let me stop anyone who wants to.No, but some Canon and Nikon cameras output their adjustment settings, Pentax doesn't, which means you can only use the shot by shot comparison analysis method.
You'd still need to check the results by the basic newspaper/cornflake packet or similar method to make sure the software has done its job, so why not do that in the first place?!
John K
John K
Posted 28/04/2013 - 22:43
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Am I missing something or doing something wrong? Earlier I was testing my K30 with 18-55 WR kit lens - it seemed to focus ok at 0 but when I adjusted the fine focus to -10 & +10 it didn't seem to make much difference. Maybe it's only noticeable on sharper lens??
Posted 28/04/2013 - 22:49
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Were you using the lens wide open? If not depth of field could hide the differences.
You also say 'it didn't seem to make much difference'. That's all it is, a fine adjustment!
John K
You also say 'it didn't seem to make much difference'. That's all it is, a fine adjustment!
John K
John K
Posted 28/04/2013 - 22:58
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jemx99 wrote:
Am I missing something or doing something wrong? Earlier I was testing my K30 with 18-55 WE kit lens - it seemed to focus ok at 0 but when I adjusted the fine focus to -10 & +10 it didn't seem to make much difference. Maybe it's only noticeable on sharper lens??
It's more noticeable on faster lenses, and wide open to minimize DOF.
Am I missing something or doing something wrong? Earlier I was testing my K30 with 18-55 WE kit lens - it seemed to focus ok at 0 but when I adjusted the fine focus to -10 & +10 it didn't seem to make much difference. Maybe it's only noticeable on sharper lens??
Peter E Smith - flickr Photostream
Posted 28/04/2013 - 22:58
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Yes I had the lens wide open and zoomed right in to view the test shots but didn't notice much difference - like you say John it is only fine adjustment but I thought I would have seen more of a difference.
Posted 28/04/2013 - 23:00
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Yes Peter I suppose f3.5 isn't really wide enough.
Posted 28/04/2013 - 23:04
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Quote:
Pic one looks spot on to me, Nurse Todd is not in the center of the image, did you focus then recompose or change the focus point away from the center area to one of the outlying ones? if so you have intoduced an error in to your calculations.
Agree with this. The framing, and hence the centre position, in both images is different.
Pic one looks spot on to me, Nurse Todd is not in the center of the image, did you focus then recompose or change the focus point away from the center area to one of the outlying ones? if so you have intoduced an error in to your calculations.
Best regards, John
Posted 28/04/2013 - 23:12
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In any event, the letter H has itself got depth, so it's not a line to mark a point.
Brian's point is that the camera has moved between exposures, so the centre point, which is preumably where you have focused, has changed. In both images the centre point is sharpest but the piece of text is different.
It needs to be a more precise experiment, especially as you are adjusting in tiny increments. If the experimental error is larger than those increments then the results will not be reliable.
Brian's point is that the camera has moved between exposures, so the centre point, which is preumably where you have focused, has changed. In both images the centre point is sharpest but the piece of text is different.
It needs to be a more precise experiment, especially as you are adjusting in tiny increments. If the experimental error is larger than those increments then the results will not be reliable.
Best regards, John
Posted 28/04/2013 - 23:13
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McBrian wrote:
You can see easily the 2nd image is the correct one. Image one is back focussed. He did state what line he focussed upon.
JAK wrote:
This was my test with the DFA 100mm f2.8 macro on the K-5:
I focussed on the line 'However Nurse Todd' but the image would lead you to believe it was three lines up from that as it was back focussing.
After dialling in a +4 adjustment I got this:
Which is what I should have got the first time. It's that simple!
John K
Pic one looks spot on to me, Nurse Todd is not in the center of the image, did you focus then recompose or change the focus point away from the center area to one of the outlying ones? if so you have intoduced an error in to your calculations.This was my test with the DFA 100mm f2.8 macro on the K-5:
I focussed on the line 'However Nurse Todd' but the image would lead you to believe it was three lines up from that as it was back focussing.
After dialling in a +4 adjustment I got this:
Which is what I should have got the first time. It's that simple!
John K
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
Posted 28/04/2013 - 23:17
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They were just two of a number of real world hand held shots taken over 10 minutes or so because I suspected back focusing. On others in between I dialled it in the wrong way and made it worse! It appears cured now.
Double checked the adjustment with a wordsearch on the back of a cornflake packet.
John K
Double checked the adjustment with a wordsearch on the back of a cornflake packet.
John K
John K
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1903 posts
22 years
The Kingdom of Fife
Not camera specific as far as I can see.
If you read half a book do you then know the true ending :
John K
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.