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Fb tube defaults

Posted: 04.10.2017 17:55
by phendley
I am not sure where to post bf tube questions - please advise on preferred location

Received my tube yesterday - very excited. Ran a stack yesterday and found the step distance to be very small - lovely image though. I could not distinguish between processing a 200 image stack one processed using just the even number images which suggested I could use a step distance twice as high as that recommended by the configuration app for my 100 mm L canon lens since that many slices would not work for quick field work. However, it was great for studio images.

Presumably , if I want to reset things easily without "spoiling" the supplied parameters for the canon 100mm , all I need to do is to create a "dummy 75", dummy 100 and dummy 125 lens (for f16) and upload the data from that using the configuration app. I understand the software does not recognize the lens so will not mind if I use a different "lens name"??

I also found that my 2 year old 100mm canon L 2.8 lens does not seem to step properly in live view on th e5DSR - does that mean it does not qualify as a recent canon lens?

Is there somewhere where users are posting their fb tube images and experiences? I would like to share learning and mistakes??

Sorry for all this newbie stuff

Re: Fb tube defaults

Posted: 05.10.2017 14:40
by Stas Yatsenko
You're welcome to share your shooting and stacking results in our Facebook group: It's quite active and engaged, there are many professional and amateur photographers among group members. Although it's mainly about focus stacking, there are members that have a tube and use it for focus bracketing.

As for the step size, you're welcome to re-adjust the recommended step size according to your needs. If you need to change the step once, you can delete the value in the 'Recommended step' windows and enter the one you find correct. If you would like to keep this value for the next configuration sessions, not having to type it in each time you re-configure the tube, you need to press the 'Save' button. In this case the '*' sign will be added to the lens name (* Canon EF 100mm f/2.8L Macro) and you will be able to find it in the User lenses section of the lens list. This allows to keep all of the initial lenses and recommended step sizes and to have your user settings for the lens under a similar lens name.

Could you please specify what exactly you mean when you say that the tube does not step properly in LV mode?

Re: Fb tube defaults

Posted: 05.10.2017 15:22
by phendley
thanks for the quick response. I am still confused about that the other part of my question - I think I understand that the tube does not actually "recognize" a lens but I guess the numbers and how they vary between lenses for a range of apertures must reflect specific internal mechanics of each lens and how much focus change is created by their response to a certain degree of lens rotation?

Regarding the live view issue -with the 5DSR set on live view and using continuous slow or continuous fast capture, the forward step was very small when set to 75; when I switched off the Live view it went from front to back in 17 steps with no problem. I had a my studio flash trigger operating the flash unit.

My Canon 100 mm L f2.8 was purchased in December 2015 so I wondered if this qualified as a "new canon lens only" per the manual. I will post the images when I get permission to access the fb site - thanks

Re: Fb tube defaults

Posted: 09.10.2017 09:41
by Stas Yatsenko
The step size is proportional to the rotation of the focus ring, it’s not linear, it’s in arbitrary units. There’s no formula to calculate how the step size varies from one lens to another one, since there’s a number of factors that influence it, involving, as you say correct, the specifics of internal mechanics.

As for the Live View, it shouldn’t be so, the number of steps should be the same with Live View mode on or off. The shooting speed may be different in Live View, but the step size should remain the same. We’ve been trying to reproduce this on a similar camera body, but didn’t manage to – it’s the same with or without Live View. Could you please compare the number of steps by making single shots and give us the idea of the difference in number of steps that you observe?

This lens should work ok in manual focusing mode, do you have problems focusing manually?