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02-12-2014, 02:06 PM   #1
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back and front focus

can someone please advise about the back and front focus what exactly is it? and does it have to be calibrated for all lens or just third party lens

02-12-2014, 02:19 PM   #2
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Front focus is when you focus on your target and the focus is actually in front of the intended target. Back focus is much the same just behind you intended target. It can be caused by the lens or the body. Depending on what body you have you will have either a global front/back focus adjustment or a adjustment for each lens as the camera will remember the settings for the lens you are adjusting. There are charts that you can download online that can allow you to adjust this and there is a procedure for doing it. The best option to calibrate for this is: LensAlign MkII Focus Calibration System LA-LA2 B&H Photo Video

Last edited by j2photos; 02-12-2014 at 02:52 PM.
02-12-2014, 02:47 PM   #3
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To correct - it can be caused by the camera body or the lens.
Back and front focus is when a camera consistently misses focus, by the same relative amount. It thinks it locked focus, but its actually a centimeter in front or behind, for example.
This can also be caused by certain body/lens combinations, when the tolerances of the two are on other extremes. In those cases, you want to add the AF adjustment only for that lens. This does not mean that all cameras of one type will front focus with a lens of another - it depends on the individual lens and individual camera body, but a series can be an indicator.
Digital cameras have functions in the menu to adjust the AF to make it more accurate. There are tutorials and focus charts available that help you do that. Just search the forums or googles
02-12-2014, 02:48 PM   #4
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Give this a read
Fixing Front and Back Focus - Introduction - PentaxForums.com

02-12-2014, 02:52 PM   #5
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QuoteOriginally posted by Na Horuk Quote
To correct - it can be caused by the camera body or the lens.
Back and front focus is when a camera consistently misses focus, by the same relative amount. It thinks it locked focus, but its actually a centimeter in front or behind, for example.
This can also be caused by certain body/lens combinations, when the tolerances of the two are on other extremes. In those cases, you want to add the AF adjustment only for that lens. This does not mean that all cameras of one type will front focus with a lens of another - it depends on the individual lens and individual camera body, but a series can be an indicator.
Digital cameras have functions in the menu to adjust the AF to make it more accurate. There are tutorials and focus charts available that help you do that. Just search the forums or googles
Thank you for catching my blunder, I guess I zoned out. Correct it
02-12-2014, 03:05 PM   #6
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thank you
02-12-2014, 03:18 PM   #7
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QuoteOriginally posted by Na Horuk Quote
Digital cameras have functions in the menu to adjust the AF to make it more accurate.
Some do. Some don't.
The more pro/enthusiast models of other brands do. I think all the pentax DSLRs do.
02-12-2014, 03:26 PM   #8
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QuoteOriginally posted by narual Quote
I think all the pentax DSLRs do.
Only from K20D forward.

02-12-2014, 04:40 PM   #9
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And there are also other limitations - some models only have a "global" AF adjust (independent of lens), while others remember the individual settings for up to a certain number of lenses
02-12-2014, 05:21 PM   #10
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And with the adjust scale in the camera, which is front and back? Left=front / right=back? It's never been clear to me.
02-12-2014, 06:36 PM   #11
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so my k5 with da dal lens .. i should nt need to calibrate this? circle yes or no
02-12-2014, 08:02 PM   #12
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QuoteOriginally posted by colourful64 Quote
so my k5 with da dal lens .. i should nt need to calibrate this? circle yes or no
Best to test to be sure. My DA 70 LTD is bang on with my K5. Yet to check it on my K5 IIs, but I expect it should be fine.
02-12-2014, 08:56 PM   #13
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I am trying to calibrate my 15LTD and my wife threw away my focus chart
02-13-2014, 09:06 AM   #14
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QuoteOriginally posted by colourful64 Quote
so my k5 with da dal lens .. i should nt need to calibrate this? circle yes or no
I don't mean to sound flip, but that's like asking us if you need glasses. We have no way of knowing. You need to test your lens on your camera to find out. It's been my experience (2 K20Ds, and a K-5IIs) with several lenses that most body/lens combinations need a slight adjustment.
02-13-2014, 10:42 AM   #15
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Well you did sound flip... i asked a question because I did not understand... not because I was stupid.. it's because I had no idea... If you are not on here to help in some way, share information or at least be entertaining you should just find yourself another site to share your bitterness... or learn to refrain from hitting the enter button...
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