Lens calibration - Focus Tune software


Smeggypants

Link Posted 27/04/2013 - 18:49
JohnX wrote:


But in order to calibrate your lenses manually you'd be taking a fair number of shots anyway wouldn't you?

well sure but using the cornflake pack method you just 'shoot em', 'look at 'em', and 'delete 'em'.
[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

Smeggypants

Link Posted 27/04/2013 - 18:54
JohnX wrote:
JAK wrote:
That does seem like a lot of work and I'm not sure you'd end up with a different result than if you'd used a page of newsprint or a cornflake box, especially if it has a word search puzzle on the back.
I'm sure that program was written by a former civil servant! Having to take shots in quadruplicate, then repeat the process even though the graph makes it obvious where the optimum is.
Perhaps OK if you have nothing else to do!

John K

I suppose the 'beauty' of the software is that it takes me out of the equation. Could I tell the difference by eye between a shot at -2 adjustment and one at -3? What about AF drift? And as to lot of work, just how long does it take to reel off 4 shots per adjustment?

At the end of it, however, if you're happy with your shots, however you arrived at them, that's all that counts.

I think I'm just persuading myself to buy the software.

By the same logic you should never ever look at your photos, which will also take you out of the equation.
[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

JAK

Link Posted 27/04/2013 - 19:22
JohnX wrote:
Could I tell the difference by eye between a shot at -2 adjustment and one at -3?

Yes you would, or you certainly should be able to. You might even wish for a -2 setting.

JohnX wrote:
What about AF drift?

The software package would only take into account the shots taken during the test. So if it is an issue it won't go away.

JohnX wrote:
And as to lot of work, just how long does it take to reel off 4 shots per adjustment?

Probably not long in itself, but you have to set it up, take those shots, sort out the folders import the shots, and then import them again. The software won't set the camera, you still have to do that yourself!

And you'll save a few $$ into the bargain. Having set my 100mmm there is no way I'd wished to have that software solution, it really isn't necessary. Are you sure you have a lens that is out of AF adjustment? If you think you have then it is easy to fix it yourself. The software will not tell you what setting you need to enter into the camera to put the AF right, you'll still need to experiment to get it correct.

If you buy it and it doesn't help, I doubt you'd get your money back. Hear his comment as to why they don't do a fully functioning trial version.

If the newspaper / cornflake box method doesn't work for you, that software wouldn't help either.

John K
John K
Last Edited by JAK on 27/04/2013 - 19:34

JAK

Link Posted 27/04/2013 - 19:55
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
John K
Last Edited by JAK on 27/04/2013 - 19:56

Smeggypants

Link Posted 27/04/2013 - 20:32
JAK wrote:
It's that simple!

John K

It is indeed.

In practice I take a few at different focal distances as well, but I just look at them on the LCD screen adn delete them
[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

McBrian

Link Posted 27/04/2013 - 20:35
JAK wrote:

The software will not tell you what setting you need to enter into the camera to put the AF right, you'll still need to experiment to get it correct.

Have you watched the video or am I missing/missunderstanding something? my understanding is this is precisely what the software does tell you.

If you ware varifocal glasses as I do you my realise that something like this could be very useful
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.
Last Edited by McBrian on 27/04/2013 - 20:37

JAK

Link Posted 27/04/2013 - 20:47
Is the software camera specific?
If it is it might show the correct number to dial in, if it isn't then it probably won't. Some cameras have different gaps and a -20 to + 20 range.

John K

Edit: Yes I did watch a few minutes of it but got bored, it seemed so much effort for something so simple.
John K
Last Edited by JAK on 27/04/2013 - 20:54

Mannesty

Link Posted 27/04/2013 - 22:32
McBrian wrote:
JAK wrote:

The software will not tell you what setting you need to enter into the camera to put the AF right, you'll still need to experiment to get it correct.

Have you watched the video or am I missing/missunderstanding something? my understanding is this is precisely what the software does tell you.

You have it right Brian, by checking each lens at each possible adjustment, the software eventually determines which setting gives the best focus accuracy at the chosen focus point.

McBrian wrote:

If you ware varifocal glasses as I do you my realise that something like this could be very useful

I do. Aren't they a pain when you need to look through a viewfinder.
Peter E Smith

My flickr Photostream
Last Edited by Mannesty on 27/04/2013 - 22:33

McBrian

Link Posted 28/04/2013 - 09:39
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.
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.

McBrian

Link Posted 28/04/2013 - 09:41
JAK wrote:
Is the software camera specific?
If it is it might show the correct number to dial in, if it isn't then it probably won't. Some cameras have different gaps and a -20 to + 20 range.

John K

Edit: Yes I did watch a few minutes of it but got bored, it seemed so much effort for something so simple.

Not camera specific as far as I can see.

If you read half a book do you then know the true ending
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.

Algernon

Link Posted 28/04/2013 - 09:50
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.

John K

The actual focus point might not coincide exactly with the red crosss
So it's possible that you are focusing on the line above or the line
below.

It's better to focus on something parallel to the back of the camera
as per the lens align jig or even a vertical box.

-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 28/04/2013 - 09:50

Mannesty

Link Posted 28/04/2013 - 10:00
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.
Peter E Smith

My flickr Photostream

JAK

Link Posted 28/04/2013 - 10:10
I focussed on the 'H' in 'However'. In pic 1 that clearly is out of focus, in pic 2 it looks good to me. I normally focus and recompose but in those kept the 'H' in the centre.

Algernon wrote:
The actual focus point might not coincide exactly with the red crosss

So it's possible that you are focusing on the line above or the line
below.

It's better to focus on something parallel to the back of the camera
as per the lens align jig or even a vertical box.

What red cross? My K-5 has a red square. Anyhow, why focus on something parallel to the sensor when you are trying to determine the focus point. The whole idea is to have something at about 45 degrees to the sensor to ascertain the actual focus point. If it was parallel you'd have nothing to know if it was better elsewhere.

It's also more of a real test because I am using the camera in the way I normally do.

Still odd that the focus is spot on on the K-m with that lens.

John K
John K

JAK

Link Posted 28/04/2013 - 10:12
McBrian wrote:
Not camera specific as far as I can see.

If you read half a book do you then know the true ending

Some books aren't worth the effort.

John K
John K

Algernon

Link Posted 28/04/2013 - 10:39
I often use a Brita refil box with a piece of black electrical tape on it to focus.
Since this picture I've also stuck a vertical piece on.




It's quite easy to see if the focus is correct what are actually print dots appear as 45 deg lines
(even though they are dots ) I've also
deliberately let dust stick to the tape which
can't be seen when OOF.




This also has the advantage that I can test 'trap/catch focus'
by racking the camera on a focus rail.


-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 28/04/2013 - 11:03
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