Search results for 'back focus' - page 1891
Fine focus adjusted but still back focuses!!!
ps ....are you doing an "apply all" AF/FA adjustment, or two individual ones for each lens ie "apply one" I believe that if the lens isn't identified the only option given is 'apply all', or at least that's what the K-5 manual states. It is said that Sigma reverse engineer the electronics for the P...
Posted by JAK on 04/02/2019 - 23:49
Fine focus adjusted but still back focuses!!!
Thanks for the reply's. The fine focus is 'apply one' not 'apply all'. the two lenses needed differing values to correct things. The issue has been around a while over various scenes so I don't think it was a case of missing the focus on the door edge. I focused a few times to ensure that It was rig...
Posted by johnducguz on 05/02/2019 - 19:14
Fine focus adjusted but still back focuses!!!
I think your issue may be that a zoom cannot be fine-focus adjusted for all focal lengths, you can only adjust it at an 'average' setting and it may well be out for other focal lengths. Also, as others have mentioned, the AF on Pentax cameras is not infallible and you can get different results on t...
Posted by davidstorm on 05/02/2019 - 21:44
Fine focus adjusted but still back focuses!!!
Thanks for the reply's. The fine focus is 'apply one' not 'apply all'. the two lenses needed differing values to correct things. The issue has been around a while over various scenes so I don't think it was a case of missing the focus on the door edge. I focused a few times to ensure that It was rig...
Posted by pschlute on 06/02/2019 - 00:07
Fine focus adjusted but still back focuses!!!
Odd that the lens can be adjusted correctly when using a focus chart but not in the real world. The only other thing to suggest is to do your lens AF/FA in outside daylight. Some artificial light can affect the AF accuracy. Focus shift ! https://photographylife.com/what-is-focus-shift Also as yo...
Posted by JAK on 06/02/2019 - 01:28
Fine focus adjusted but still back focuses!!!
i thought focus shift only affected fast lenses. I would not have thought a 2.8 lens would experience it.
Posted by pschlute on 06/02/2019 - 10:48
Fine focus adjusted but still back focuses!!!
To the OP, have you tried repeating the test on other outdoor subjects to see if the back focus issue remains consistently out? If it is reset the K-5 to the default setting and try again before resetting any fine AF adjustments. If still a problem after that try the lens on a different camera bod...
Posted by JAK on 06/02/2019 - 12:54
Fine focus adjusted but still back focuses!!!
The test sheets were shot indoors but with natural light from windows so I don't think the issue is colour temp. It's not a one off problem, the issue has been around for some time, I was just too lazy to do anything about it till now. It's happened in a range of situations, in bright sun, cloud, sh...
Posted by johnducguz on 06/02/2019 - 18:10
Fine focus adjusted but still back focuses!!!
Just one further thought / question on this: When you took the images of the test chart with both lenses, were you exactly the same distance away from the central point of the test chart as you were from the edge of the door in the outside shots? If not, it is not a fair / good comparison. Your...
Posted by davidstorm on 06/02/2019 - 18:33
Fine focus adjusted but still back focuses!!!
Nope, distances were about 2-3 ft with the charts & about 7-10 ft with the door. On a recent shoot the distance was about 15-20 ft. The distance doesn't seem to matter, back focusing occurs. I may be dumb here but if the focus is fine at say 6 ft but not 12 ft, am I to shoot at 6ft away at all times...
Posted by johnducguz on 06/02/2019 - 20:22
Fine focus adjusted but still back focuses!!!
Nope, distances were about 2-3 ft with the charts & about 7-10 ft with the door. On a recent shoot the distance was about 15-20 ft. The distance doesn't seem to matter, back focusing occurs. I may be dumb here but if the focus is fine at say 6 ft but not 12 ft, am I to shoot at 6ft away at all times...
Posted by davidstorm on 06/02/2019 - 21:14
Fine focus adjusted but still back focuses!!!
Focus adjustment can simply be very tricky with a zoom lens. Worst case scenario is things are out + one end of the zoom and out - at the other. Personally I'd be aiming for the end of the zoom I'm most likely to use, and aiming to focus adjust there.
Posted by richandfleur on 06/02/2019 - 23:09
Fine focus adjusted but still back focuses!!!
I'd read about fine focus of a zoom being tricky which is why I went for the 70mm end as that's what I use the most. I'm going to wait for the weekend & try the zoom on my other body to see what happens then.
Posted by johnducguz on 07/02/2019 - 17:44
Fine focus adjusted but still back focuses!!!
Isn't it better to optimise for the long end of a zoom rather than the short end? i.e. wide angle > greater depth of field.
Posted by pgweber on 07/02/2019 - 17:50
Fine focus adjusted but still back focuses!!!
does the lens focus accurately in live view?
Posted by redbusa99 on 07/02/2019 - 18:13
Fine focus adjusted but still back focuses!!!
I did optimise the long end, it's a 24-70. Not tried live view, I've never used it. Never thought i'd need to if the body & lens could manage to work together. If I've got to start manual focusing I may as well get a 6x7.
Posted by johnducguz on 07/02/2019 - 18:23
Fine focus adjusted but still back focuses!!!
does the lens focus accurately in live view? I did optimise the long end, it's a 24-70. Not tried live view, I've never used it. Never thought i'd need to if the body & lens could manage to work together. If I've got to start manual focusing I may as well get a 6x7. It doesn't involve manual focussi...
Posted by JAK on 07/02/2019 - 18:34
Fine focus adjusted but still back focuses!!!
Had a quick read, thanks a lot, but unless I'm missing something, which is possible 'cause it's the 1st time i've ever read about Live View, you wouldn't be able to use it when shooting a model for example who is changing their pose every second. For a still life I think I get it but is it a useful ...
Posted by johnducguz on 07/02/2019 - 19:05
Fine focus adjusted but still back focuses!!!
you wouldn't be able to use it when shooting a model for example who is changing their pose every second. Try it and see! Some prefer live view (normally mirrorless fans) and some don't. There's no reason for it not being able to do what you want if you can cope with the image on the back screen....
Posted by JAK on 07/02/2019 - 19:12
Fine focus adjusted but still back focuses!!!
You can use live view to check the accuracy of your af, and keep adjusting till both are the same. Live view is not affected by front or back focus issues. Take a test shot using live view, this should be accurate. Now switch back to vf, and fine tune to match your test shot.
Posted by derek897 on 07/02/2019 - 19:56
