Really slow focus on FE 2.9/90mm on A7RII and suggestion for some improvements

[loomitz]

first of all thanks for your work, I tested the program with the a7RII and I can say it works well, I've testing with the lens, F2.8 GM 24-70 (this works fast and exceptionally) with 90mm F2.8 macro (focus takes a long time to start) and a canon lens adapted with metabones and I can say it works seamlessly with the new metabones native mode, focus a little slow but it works.

Also prove with my a6000 APSC lenses, the 55-210 and 16-50, they work smoothly.

I think the lens that giveme trouble was sadly the more necessary, it would be the 90mm macro, for some reason, with this lens the number of shots is really limited some times only 8 (which I think is easier to solve) and the speed of focus is very slow.

thanks for your attention, and if i can help im something im happy to try.

[obs1dium]

with this lens the number of shots is really limited

The number of shots is limited by the focusing range, which is divided into discrete steps. For the lenses I tested, the total range consists of 120 steps.
I don't know if your macro lens simply has a narrower range, but it's a possibility.

[loomitz]

Thanks, for the reply, the detail with macro lenses is that the path of the barrel is much longer in a shorter distance, for example the distance between 0.92 feet and 1.5 feet is much longer in a macro but the app detects that it is short and gives only a few shots.

I upload a video of the operation of the app with this lens and the other two I have.

https://youtu.be/NXhTEXnur3k

I hope that helps in something

[obs1dium]

Interesting. Focusing ranges appear to be the same, but focusing speed could indeed be improved.
In the first test, you selected about 1/6th of the total range, so 20 pictures is exactly what you should expect.

[loomitz]

ok , I think I understand about the focusing range, but about the the speed of focus I think it has to do something with barrel turns difference between MF and AF lens , the camera always in MF .

example for better understanding.

https://www.youtube.com/watch?v=tsWwzLGx4Gc

[3ricj]

Wow, wait, so this works on the a7rII but not the a7r? Should I try installing the latest version (eg: the new one might work) or is it more that there is a bug specific to the a7r? I am using the same 90mm lens.

[loomitz]

Try this, Put the lens the 90mm, in Auto Focus (the ring up), but the camera focus mode in manual, thats the only way that works on A7RII, its slow but works you will notice that you have to do a lot of turns more for focus.

[3ricj]

I have completed a full removal and reinstall of version 1.2. It still locks up/hangs when I press O at the max position and then the app no longer responds. I have tried your method as described, with the lens on AF and camera setting to be on DMF and MF without any luck.

[obs1dium]

It still locks up/hangs when I press O at the max position

It's possible that your camera does not support the method I use to adjust focus.

[MartinNuc]

I have this lens too and i can confirm it shoots bracketed photos but focusing is very slow. Lens focus ring on AF, camera settings MF.

The first thing I think could help is just to reverse focusQueue (https://github.com/obs1dium/FocusBracket/blob/master/app/src/main/java/com/obsidium/focusbracket/FocusActivity.java#L234). Here is why:

First you set minimum focus. After that you set maximum focus. Therefore the focus ring is in the maximum focus position. When starting shooting the app first moves focus to the minimum position. On 90mm lens this takes a long time. If we start shooting from the maximum position and move to the minimum after we will save some time at the beginning. Made PR #15

Another option is to first pick maximum focus position and pick minimum focus position after.

[obs1dium]

You could try and check if the FocusDriveListener gets called at all with that lens.

[MartinNuc]

If FocusDriverListener would not be called it would take no photos at all, am I right?

[obs1dium]

Err, right. I thought I was checking the focus position in another place as well, but apparently not.

[pdykmans]

This reminds me of a problem I had when doing a similar thing for Magic Lantern (Canon). Now, I'm very new to Sony, so I can't say for sure that the problem is the same. But the issue I had with focusing on the Canon system was that the discrete steps in the focusing range behaved totally different depending on the lens. E.g. sometimes the discrete steps were linear with focusing distance, sometimes the relationship was logarithmic, and especially with cheaper lenses there was hardly a correlation between the two. There was one lens where focussing increments required +4 to actually move the lens one step. And when that lens was steered with +1 increments it would simply not move at all (and therefore freeze the program). I also found a rather wild variety in the total number of steps that any lens would support.

My theory at the time was that it depended on the motor system of the lens. E.g. a stepper motor can be controlled very discretely. But other motor types might not. If that makes any sense...

In the end I found no other way (at least for the difficult lenses) than to record the stepping range into a hard coded dictionary, mapped against their linear distance. Ugly as hell, I know :-)

That said, I tested this FocusBracket app on my Sony A6000. With the Sony 50mm 1.8 it is very slow (but it works). With the 18-105mm OSS it works much faster.

B.t.w. thanks for the app Obs1dium!

Regards,
Philippe

[obs1dium]

Thanks for the insight, it could very well be that these kinds of issues also affect Sony cameras and lenses.

I recently upgraded from the A5100 to an A6000, and surprisingly focusing with the kit lens is extremely slow now. Not sure why that is, loomitz mentioned in the first post that this camera/lens combination works smoothly.

The only other two autofocus lenses I own (Sigma 19 and 30) are working fine.