[markcphoto]

I got a new samyang 85, focus confirmation on it is off by a fair amount. not a massive deal really. But does anyone know if it's possible to program this to work somehow?

[Adam]

I got a new samyang 85, focus confirmation on it is off by a fair amount. not a massive deal really. But does anyone know if it's possible to program this to work somehow?

There's a degree of tolerance in the system, and since F1.4 delivers very shallow DoF, I can see how the AF confirmation might seem unreliable.

Generally the solution would be just to stop down more, but you could also mess with a global AF adjustment. Just bear in mind that this could mess up the performance of your other lenses while set.

[pschlute]

If you do follow Adam's advice and use the AF fine adjustment in the camera (I do this for all my lenses) make sure you do it in a methodical fashion. Have a search on here for the right technique.

Depending on how close your subject is, at 1.4 breathing in or out as you take the photo can make all the difference to the point of focus, but there is one possible other explanation fi you are seeing out of focus pictures when using an aperture smaller than f1.4. Have a read up on "focus shift" What is Focus Shift?

[biz-engineer]

I got a new samyang 85, focus confirmation on it is off by a fair amount. not a massive deal really. But does anyone know if it's possible to program this to work somehow?

AF can be microadjusted, but I doubt that will practically work because the AF confirmation range is too wide for 85 1.4 wide open. Live view (using outdoor setting if necessary) with focus peaking is the way to go. I've used LV focus peaking with the Samyang 135 f2 wide open with lots of success.

---------- Post added 23-10-17 at 07:47 ----------

Have a read up on "focus shift" What is Focus Shift?

Focus shift is a problem that occur when stopping down the lens aperture. That's a problem when focusing in LV mode with camera stopping down the lens to accommodate light intensity to the video frame rate of the LV mode, then opening up the diaphragm, to take the shot. That's not the case here with having DoF range narrower than range of PDAF confirmation in the viewfinder.

[markcphoto]

Thanks for the replies. I did already try the global AF fine adjust but that didn't work, looks like i'd need to go to about -15 or so. I've tried this on a tripod so i don't think technique is the problem. I can kind of get results if i stop down past 2.8, i just set it to closest focus and once i get focus confirmation i just give it about 2 or 3 degrees more of a twist and that usually gets it close enough. Pity there isn't a way to program these things past the fine adjustment settings.

I got it on ebay from china so sending it back probably isn't worth the hassle, and i'll probably mostly use it with flash past f5.6 or landscapes anyway.

[clackers]

Thanks for the replies. I did already try the global AF fine adjust but that didn't work, looks like i'd need to go to about -15 or so. I've tried this on a tripod so i don't think technique is the problem. I can kind of get results if i stop down past 2.8, i just set it to closest focus and once i get focus confirmation i just give it about 2 or 3 degrees more of a twist and that usually gets it close enough. Pity there isn't a way to program these things past the fine adjustment settings.

I got it on ebay from china so sending it back probably isn't worth the hassle, and i'll probably mostly use it with flash past f5.6 or landscapes anyway.

There must be something misaligned inside for it to be beyond -10, if your other lenses are okay. This isn't affecting your image quality (contrast, sharpness)? You should do a decentering check, Mark.

[Dgr]

There must be something misaligned inside for it to be beyond -10, if your other lenses are okay. This isn't affecting your image quality (contrast, sharpness)? You should do a decentering check, Mark.

I always wondered about that - focus confirmation works through the lens, right? So in other words, the camera needs to "see" a sharp image to confirm it. If the camera saw a sharp image, why isn't the photo sharp (sometimes even in the center)? It's not like the confirmation mechanism can correct a misaligned lens and light up where the image was supposed to be sharp, but was not due to misalignment.

[clackers]

I always wondered about that - focus confirmation works through the lens, right? So in other words, the camera needs to "see" a sharp image to confirm it. If the camera saw a sharp image, why isn't the photo sharp (sometimes even in the center)? It's not like the confirmation mechanism can correct a misaligned lens and light up where the image was supposed to be sharp, but was not due to misalignment.

Yeah, but the focus confirmation is occurring in the AF module, not the sensor where the picture is actually taken.

If everything is aligned correctly, of course one should agree with the other.

[TwoUptons]

I have focus issues with mine, too, but most of my issues stem from my moving between focus and shot... the problem is much less when the camera is on a tripod.

And using live view just makes the problem worse when hand holding because I move more...

-Eric

[hadi]

for what its worth, i have the lens and i'm using it on the k1.
i also have the spyder lens-cal tool.
fine-adjusting or manually adjusting your lens to recognize when its in focus may work for automatic lenses. but not manual lenses.

also, the samyang may show its in focus via view-finder, and also via the lcd. yet when i take the picture, it comes out as complete blur. shutter shake, maybe.
even if i set up on tripod, use a crazy fast shutter at 1/5000 or higher, it still gives a blur smear.
it works beautifully after f2. but f1.4 or f1.8 is almost useless images. pity, as i really want to like the lens