# Reikan FoCal Testing Distance and Accuracy



## llcanon (Jun 5, 2012)

In the FoCal manual, it says Canon recommends 50x focal length for testing distance. I did a DoF calculation. For 200mm, you would place the camera 10m away from the target if following Canon's recommendation. At this distance and f2.8, the DoF is 0.26m with 0.13m for both front and back. So the tolerance of in-focus is pretty loose. If you place the camera 25x focal length, the DoF is only 0.06m which is much shallower. I don't know how sensitive FoCal is in detecting the sharpness difference, but I would definitely place the camera closer in hope to improve the testing accuracy. Plus 50x focal length is too far a shooting distance in practice for non- super tele-lens. 25xfocal length appears to be a good distance to use. Any thoughts? Thank you!


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## neuroanatomist (Jun 5, 2012)

I test my lenses at both 25x (recommended by LensAlign) and 50x, and the results usually differ. I take both into account, along with usual shooting distance, in selecting an AFMA. 50x is a reasonable distance for many subjects with shorter focal lengths.


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## Mt Spokane Photography (Jun 5, 2012)

llcanon said:


> In the FoCal manual, it says Canon recommends 50x focal length for testing distance. I did a DoF calculation. For 200mm, you would place the camera 10m away from the target if following Canon's recommendation. At this distance and f2.8, the DoF is 0.26m with 0.13m for both front and back. So the tolerance of in-focus is pretty loose. If you place the camera 25x focal length, the DoF is only 0.06m which is much shallower. I don't know how sensitive FoCal is in detecting the sharpness difference, but I would definitely place the camera closer in hope to improve the testing accuracy. Plus 50x focal length is too far a shooting distance in practice for non- super tele-lens. 25xfocal length appears to be a good distance to use. Any thoughts? Thank you!


 
AFMA settings will vary with distance. The 50X distance is not going to be optimal for those who like to get close.
Here is a screen shot of one of the tests I ran. Its pretty obvious as to where the best AFMA lies, so the main thing is to adjust it at the distance you use. 

If you shoot your 200mm lens at 2 meters, then adjust it there. All lenses tend to front focus at close distances. The 50X distance applies where your typical image is not a close focus image.

I hope that explains it a bit.


With focal, you are going to get a curve like this, with the peak being obvious. Being off by a couple of AFMA units usually makes very little distance.

HOWEVER, the curve may shift left or right depending on the distance, and near mfd, it can be a big difference.


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## Viggo (Jun 6, 2012)

Since this thread is nearly accurate to my question, I don't bother with a new thread;

Why won't the FoCal Pro recognize my 5d2's?? 

I have entered serialnumbers on my profile, copied the new license over to the program. I plug it in, Windows prompts me to "open with" sort of stuff, but NOTHING happens in FoCal. 

I do the same with my 5d3 and it pops up immediately.

The 5d2's (two of them) just displays what it would under normal shooting conditions, and if I squeeze the shutter, it just says "Busy". Now, I read something about changing usb-modes, but how can I do that when I can do nothing with the camera, just "busy"

Oh, and i have the 1.44 version.

Any ideas please?


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## Drizzt321 (Jun 6, 2012)

Viggo said:


> Since this thread is nearly accurate to my question, I don't bother with a new thread;
> 
> Why won't the FoCal Pro recognize my 5d2's??
> 
> ...



Maybe you should try emailing (or posting on FB) Reikan about this?


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## cliffwang (Jun 6, 2012)

Viggo said:


> Since this thread is nearly accurate to my question, I don't bother with a new thread;
> 
> Why won't the FoCal Pro recognize my 5d2's??
> 
> ...



Have you tried to re-install 5D2 driver?


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## Viggo (Jun 6, 2012)

cliffwang said:


> Viggo said:
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> > Since this thread is nearly accurate to my question, I don't bother with a new thread;
> ...



In danger of sounding very stupid, what driver? I didn't install anything for the 5d3 to work on my stoneage XP laptop (mac user). I tried VirtualBox with Windows7 ultimate, but then it did not recognize my 5d3 either.


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## Viggo (Jun 6, 2012)

Drizzt321 said:


> Viggo said:
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> 
> > Since this thread is nearly accurate to my question, I don't bother with a new thread;
> ...



Yes, I have, only this was kind of in a hurry to get fixed (wedding shoot) so I try everything!


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## cliffwang (Jun 7, 2012)

Viggo said:


> cliffwang said:
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> > Viggo said:
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Does EOS Utility work for your 5D2? Anyway, try to download USBDeview from the following webpage.
http://www.nirsoft.net/utils/usb_devices_view.html
Use it to delete your 5D2 driver and plug your 5D2 again to see if that will work for you.


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## bkorcel (Jun 7, 2012)

I think you should install the eos utility and try again.


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## Mt Spokane Photography (Jun 7, 2012)

bkorcel said:


> I think you should install the eos utility and try again.


 

Yes, Install the EOS utility and verify that you can remotely operate the shutter.


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## Viggo (Jun 7, 2012)

Actually , yeah , you're right , it's the same problem with EOS utility... it just says busy when i push something....


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## Viggo (Jun 7, 2012)

cliffwang said:


> Viggo said:
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T H A N K Y O U !! ! !! !! That worked perfect!! Awesome! Thanks again!" ;D


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## neuroanatomist (Jun 7, 2012)

cliffwang said:


> Viggo said:
> 
> 
> > In danger of sounding very stupid, what driver? I didn't install anything for the 5d3 to work on my stoneage XP laptop (mac user). I tried VirtualBox with Windows7 ultimate, but then it did not recognize my 5d3 either.
> ...



I thought drivers were for trucks and racecars. What the hell are they doing on a computer? Gee, I'm glad to be a Mac user. :


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## Viggo (Jun 7, 2012)

neuroanatomist said:


> cliffwang said:
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Amen to that... Mac is like my old Amiga's , if the joystick didn't work , well them you hadn't plugged it in!


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## cliffwang (Jun 7, 2012)

neuroanatomist said:


> I thought drivers were for trucks and racecars. What the hell are they doing on a computer? Gee, I'm glad to be a Mac user. :


There is nothing wrong with Windows. The driver conflict usually caused by software. Windows provide a default driver for camera devices. After you install EOS utility, the driver will be updated. When you upgrade your EOS utility, the driver will be updated again. Windows is much open than Mac, so it doesn't restrict Canon for the driver update. If EOS utilty programmers have perfect coding, the new driver might bring you some benefits. On the other hand, users might face some problems when the code was not well written. Nothing is absolutely right and wrong between open and close platforms.


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## Viggo (Jun 7, 2012)

cliffwang said:


> neuroanatomist said:
> 
> 
> > I thought drivers were for trucks and racecars. What the hell are they doing on a computer? Gee, I'm glad to be a Mac user. :
> ...



For us that do not care about drivers and which code is written well and want to turn the machine on, run the software of choice to do a task. Such as turning it on, edit my raw's in Lightroom and then shut it off to shoot some more, pc and all of it's openess dosen't make sense. ;D


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## Fotofanten (Sep 9, 2012)

I just wanted to thank this forum for letting me in the know on reikan focal. Even though i bought the standard edition and did the AFMA manually, the results were just stunningly accurate. Also, the process was quite fun.

By the way, Why does everything have to turn into a mac vs pc debate? We need both systems competing to have a reasonable rate of innovation. Lets just keep it at that.


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## dawgfanjeff (Sep 9, 2012)

Viggo said:


> cliffwang said:
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This is precisely my experience on all my windows boxes...


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## AcutancePhotography (Sep 8, 2014)

I figured it would be better to necro-rez this thread than start another thread on the exact same topic (makes searching better). Mods, if I am mistaken, please let me know. 

This weekend I purchased FoCal and ran it on my lenses. I had problems following the directions concerning distance between camera and target.

First I printed out the targets on A4 paper. I went to a professional print shop and had them print and mount the targets on foam board. Really worked out well.

The first lens I wanted to check was my 35mm. The instructions recommend using a distance of 50x the focal length. 35mm x 50 = 1750mm. I placed my focal plane 1.7 meters from the target and centered my center focus point on the center of the target.

The problem was that using the target checking tool, the software was unable to detect the target. Well, small wonder because with a 35mm lens at 1.7 meters the A4 target is pretty small... too small in my opinion. In looking at the figures in the manual, it appeared to me that the camera needs to be closer.

So I moved the camera closer to the target. The new distance was 0.8 meters. Ran the target checker and there was no problem. No problems with any of the tests.

Did I miss-interprete the instructions when I orginally placed my focal plane 1.7 meters (50x FL)?

When I tested my 85mm lens I had to keep the focal plane closer (not as close as with 35mm) than the instructons.

Was printing the target at A4 (8.5x11 inches) wrong. The instructions are not very clear on that.

When ever I run in to problems like this, I immediately think of user error.  ;D

Any other FoCal users run across the same problem?


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## wtlloyd (Sep 8, 2014)

I haven't focus checked my lenses in a while, but I recall not having problems with any focal length at recommended distance.

Here is Reikan's two page advisory on correct target setup distance https://dl.dropboxusercontent.com/u/11469157/FoCal/Docs/FoCal%20Test%20Distance_1.0.pdf

Reikan expects to release Focal version 2 sometime this month. Changes may not be relevant to this thread.


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## neuroanatomist (Sep 8, 2014)

I've not had any issues with the software finding the target at 50x focal length (I test at both 25x and 50x using a target printed on 8.5x11" matte paper). 

What did FoCal report for light levels (EV)?


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## AcutancePhotography (Sep 8, 2014)

neuroanatomist said:


> What did FoCal report for light levels (EV)?



My EV was 9.9 which I think is close enough for the recommended 10.


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## neuroanatomist (Sep 8, 2014)

Yes, that should have been fine. Was the paper matte or glossy? FoCal recommends against glossy, IIRC.


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## AcutancePhotography (Sep 8, 2014)

neuroanatomist said:


> Yes, that should have been fine. Was the paper matte or glossy? FoCal recommends against glossy, IIRC.



Matte, inkjet to reduce reflections. The paper was very white though. But since I had no problems with the closer distances, I don't *think* my target was the issue, now that I know that printing it at A4 size was the right thing to do.

If I have time this week, I might try to find the distance where the target checker fails. Maybe that will tell me something. 

My primary concern is that if I calibrate at a shorter than the recommended distance (50x for shorter lenses - 20/25x for longer lenses) how off will the results be.

In reading the reports, the results for my lenses were nothing surprising. The two lenses I checked were withing +/- 5


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## kaihp (Sep 8, 2014)

AcutancePhotography said:


> The problem was that using the target checking tool, the software was unable to detect the target. Well, small wonder because with a 35mm lens at 1.7 meters the A4 target is pretty small... too small in my opinion. In looking at the figures in the manual, it appeared to me that the camera needs to be closer.
> 
> So I moved the camera closer to the target. The new distance was 0.8 meters. Ran the target checker and there was no problem. No problems with any of the tests.
> 
> Did I miss-interprete the instructions when I orginally placed my focal plane 1.7 meters (50x FL)?



Actuance, did you try to use the "Zoom" mode during Target Setup? I have found that I usually have to engage the Zoom mode to detect the target correctly during the alignment/setup check phase. But once it is setup, I've had no problems in getting FoCal to work.

Last time I tested a lens, I had an EV just below the recommended 8.0, without getting target detection problems, so a lack of light should not be your problem.


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## neuroanatomist (Sep 9, 2014)

kaihp said:


> Actuance, did you try to use the "Zoom" mode during Target Setup? I have found that I usually have to engage the Zoom mode to detect the target correctly during the alignment/setup check phase. But once it is setup, I've had no problems in getting FoCal to work.



Great point, I had forgotten about that. Personally, I just shoot the images myself and load them for manual analysis. I'd have to set the AFMA values myself anyway, and manual lets me oversample a bit.


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## Valvebounce (Sep 9, 2014)

Hi AcutancePhotography. 
I wanted to use FoCal on my Sigma 17-70C which has the option to adjust at four focal lengths, at four distances, 16 adjustments, 17mm at the farthest distance I could barely see the target and it certainly wasn't going to play well even after zoom so I printed a target on A3, just tel FoCal how long the line is and it all worked. 

Cheers, Graham.


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## AcutancePhotography (Sep 9, 2014)

kaihp said:


> Actuance, did you try to use the "Zoom" mode during Target Setup? I have found that I usually have to engage the Zoom mode to detect the target correctly during the alignment/setup check phase. But once it is setup, I've had no problems in getting FoCal to work.



Ohhh. So I should set up the target at the recommended distance (50X)
use the zoom function in FoCal for running the target check tool
then zoom out for the AFMA tests?

Is that what you mean?

I will try that! Wish the documentation for FoCal was a little clearer, but that's a general complaint I have about most software documentation. I prefer my software documentation being written by actual humans instead of programmers/coders. ;D

Thanks for the tip!


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## kaihp (Sep 9, 2014)

AcutancePhotography said:


> kaihp said:
> 
> 
> > Actuance, did you try to use the "Zoom" mode during Target Setup? I have found that I usually have to engage the Zoom mode to detect the target correctly during the alignment/setup check phase. But once it is setup, I've had no problems in getting FoCal to work.
> ...



Yes, that is exactly what I meant.


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