FoCal

Posted this question in the 1DX thread, but no replies on it. Looking for general feedback, but also any feedback from those who have used it to calibrate manually.

Anyone own FoCal? Likes/Dislikes? And what about using it with the 1DX? Something about the automatic features not available? Any less effective? Thanks.

There is quite an extensive thread about FoCal. I'll poke around and see if I can find it.

I like it alot. Have used it with 7D, 1D3, 5D2, and now 5D3.

On 5D3/1DX FoCal cannot set the MA number, you have to set it manually. So it requires some fiddling to get the adjustment done (changing the MA number in the camera's menu system).

Then if you want, you can run the focus consistency check for a few of the closest MA numbers and dial it in perfectly. I usually run a set of the 3 or 5 closest numbers, 10 shots each, and then look through the results and decide for myself what the best MA number is. Works great.

It is just as effective as with other bodies.

I used it with my 7D and loved it. Haven't tried it yet was my 5D III

The downside for me is the fact that it is attached to the PC when the shots are fired off. My PC is in a spare bedroom upstairs so it rules out testing my longer lenses (the 50 x focal length requirement). It would be nice if it could be tested without that PC connection, then reconnected so FoCal does its thing later.

Maybe thats a problem with them all?

Lowner wrote in post #15323766
The downside for me is the fact that it is attached to the PC when the shots are fired off. My PC is in a spare bedroom upstairs so it rules out testing my longer lenses (the 50 x focal length requirement). It would be nice if it could be tested without that PC connection, then reconnected so FoCal does its thing later.

Maybe thats a problem with them all?

You can't temporarily move your PC to calibrate your lenses? It's nit like you be calibrating them every day? I think a lot of people have laptops which makes it easier. You could also probably buy a cheap laptop for this purpose.

Made a big difference for me on my 7D...going through the reports was very interesting. Especially the sharpness test

https://photography-on-the.net …/showthread.php​?t=1105193

convergent wrote in post #15324081
You can't temporarily move your PC to calibrate your lenses? It's nit like you be calibrating them every day? I think a lot of people have laptops which makes it easier. You could also probably buy a cheap laptop for this purpose.

Sadly that requires just too much work. Given that my 400mm lens needs 50 x 400mm = 20000mm or 20 mts I'd need to be in our local park because even our garden is too small. As you say, a laptop would do the job but theres no way I'm buying one for just this reason.

^ Actually you only need 25x when using a longer lens like the 400mm...

I have been using FoCal for several months now and find it a useful tool when it works and a pure exercise in frustration when it does not. LIghting has to be just right to get accurate results. I have two lenses (both entry level) that I have yet to get to complete the testing process without getting error messages. Glad I bought it, but I wish it worked more consistently......

John

Lowner wrote in post #15324876
Sadly that requires just too much work. Given that my 400mm lens needs 50 x 400mm = 20000mm or 20 mts I'd need to be in our local park because even our garden is too small. As you say, a laptop would do the job but theres no way I'm buying one for just this reason.

Actually for longer focal lengths Focal recomends short multipliers. For 400mm they recommend 20X or 8 meters.

Here's a link to their recomendation by focal length
https://dl.dropbox.com …20Test%20Distan​ce_1.1.pdf

Lowner wrote in post #15323766
The downside for me is the fact that it is attached to the PC when the shots are fired off. My PC is in a spare bedroom upstairs so it rules out testing my longer lenses (the 50 x focal length requirement). It would be nice if it could be tested without that PC connection, then reconnected so FoCal does its thing later.

Maybe thats a problem with them all?

There is now an option (Manual Mode) that will read files created offline, so you don't need to be connected to your computer.

My thoughts on FoCal...highly recommended, but follow the instructions (FTFM). Make sure you have adequate lighting, target is square, you are the proper distance, etc.

Chris, I use FoCal with my 1DX. I am very pleased with the product and quite amazed with the results. I was somewhat skeptical about the idea but gave it a try. It worked just fine with the 1DX except everything has to be done manual, but FoCal tells you what to do and when to do it.

tomholman wrote in post #15325366
Chris, I use FoCal with my 1DX. I am very pleased with the product and quite amazed with the results. I was somewhat skeptical about the idea but gave it a try. It worked just fine with the 1DX except everything has to be done manual, but FoCal tells you what to do and when to do it.

Thank you! This was the feedback I was looking for.

I think I am missing something regarding calibrating the focusing of lenses. What I cannot grasp, and hopefully someone will clarify, is how can the focus error be in the lens? Does not the camera focus sensor essentially compensate for any lens error, i.e. producing the sharpest focus on the surface of the sensor for any attached lens? I can understand wherein the camera focus sensor might not be quite aligned with the image sensor, thus the need for a calibration tool such as FoCal. However, if this were the case, it would seem the same error would be introduced across every lens on a particular camera. What am I overlooking?