Back and front focusing lenses

Mtathos · 10-04-2022, 02:00 PM - **1 Like**

I was wondering about lenses back and front focusing. Is that specific to the lens or does the camera body play a role? Is the new full frame glass such as the 15-30, 24-70 and 70-200 prone to focusing issues? Is this easy to correct if it does happen and in your experience does it happen often?
Thanks in advance!
Cheers!

**othar** · 10-04-2022, 04:28 PM - **2 Likes**

It is the combination of manufacturing tolerances from the lens and the camera that determine if there is front/back focusing. Therefore a lens can front or back focus on 1 camera body and be perfectly fine on another body, depending on how those tolerances work together.

I have 1 out of 5 lenses that needed corrections (I own mostly vintage lenses), if that is lucky or common I can't say.

Just for your information: lens corrections only influence the focus when using the optical viewfinder (OVF) -> PDAF
When you use LV for focusing the camera will work with a different focusing system that doesn't need AF fine tuning -> CDAF

Mtathos · 10-04-2022, 05:10 PM

Originally posted by othar

It is the combination of manufacturing tolerances from the lens and the camera that determine if there is front/back focusing. Therefore a lens can front or back focus on 1 camera body and be perfectly fine on another body, depending on how those tolerances work together.

I have 1 out of 5 lenses that needed corrections (I own mostly vintage lenses), if that is lucky or common I can't say.

Just for your information: lens corrections only influence the focus when using the optical viewfinder (OVF) -> PDAF
When you use LV for focusing the camera will work with a different focusing system that doesn't need AF fine tuning -> CDAF

Did not know that about OVF vs. LV. Thanks for the info!

**ebahle** · 10-04-2022, 07:11 PM - **1 Like**

I have and use a spyder lens cal, linked below. I find it really quick n easy to dial in lens calibration. As noted above it’s quite random as to what adjustment will be needed with any given camera lens combo. Once I calibrated my lenses I definitely noticed a higher rate of on focus images at wide apertures

Welcome to Spyder LensCal | Datacolor

AfterPentax Mark II · 10-05-2022, 02:00 AM - **1 Like**

Originally posted by Mtathos

I was wondering about lenses back and front focusing. Is that specific to the lens or does the camera body play a role? Is the new full frame glass such as the 15-30, 24-70 and 70-200 prone to focusing issues? Is this easy to correct if it does happen and in your experience does it happen often?
Thanks in advance!
Cheers!

To be honest, I never had any problem with back or front focusing with any lens. I do have a small problem with a K-7, but to overcome that problem I shoot with LV. It is a K-7 problem, all the other camera's any lens I own work perfect on them. What I do notice is, that more modern the camera, the better the results. Example: the 18-135 I used on my early Samsung GX-10 (K10d) gave very pleasing pictures, but on the KP this lens shines. It is such a fine lens, but it needs a good camera that can handle the IQ it delivers.

10-04-2022, 02:00 PM - 1 Like	#1
Mtathos Junior Member Join Date: May 2022 Posts: 28	Back and front focusing lenses I was wondering about lenses back and front focusing. Is that specific to the lens or does the camera body play a role? Is the new full frame glass such as the 15-30, 24-70 and 70-200 prone to focusing issues? Is this easy to correct if it does happen and in your experience does it happen often? Thanks in advance! Cheers!

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10-04-2022, 04:28 PM - 2 Likes	#2
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	It is the combination of manufacturing tolerances from the lens and the camera that determine if there is front/back focusing. Therefore a lens can front or back focus on 1 camera body and be perfectly fine on another body, depending on how those tolerances work together. I have 1 out of 5 lenses that needed corrections (I own mostly vintage lenses), if that is lucky or common I can't say. Just for your information: lens corrections only influence the focus when using the optical viewfinder (OVF) -> PDAF When you use LV for focusing the camera will work with a different focusing system that doesn't need AF fine tuning -> CDAF

10-04-2022, 05:10 PM	#3
Mtathos Junior Member Join Date: May 2022 Posts: 28 Original Poster	Originally posted by othar It is the combination of manufacturing tolerances from the lens and the camera that determine if there is front/back focusing. Therefore a lens can front or back focus on 1 camera body and be perfectly fine on another body, depending on how those tolerances work together. I have 1 out of 5 lenses that needed corrections (I own mostly vintage lenses), if that is lucky or common I can't say. Just for your information: lens corrections only influence the focus when using the optical viewfinder (OVF) -> PDAF When you use LV for focusing the camera will work with a different focusing system that doesn't need AF fine tuning -> CDAF Did not know that about OVF vs. LV. Thanks for the info!

10-04-2022, 07:11 PM - 1 Like	#4
ebahle Site Supporter Join Date: Oct 2011 Location: Northern Michigan Photos: Albums Posts: 364	I have and use a spyder lens cal, linked below. I find it really quick n easy to dial in lens calibration. As noted above it’s quite random as to what adjustment will be needed with any given camera lens combo. Once I calibrated my lenses I definitely noticed a higher rate of on focus images at wide apertures Welcome to Spyder LensCal \| Datacolor

10-05-2022, 02:00 AM - 1 Like	#5
AfterPentax Mark II Pentaxian Join Date: Mar 2021 Posts: 1,462	Originally posted by Mtathos I was wondering about lenses back and front focusing. Is that specific to the lens or does the camera body play a role? Is the new full frame glass such as the 15-30, 24-70 and 70-200 prone to focusing issues? Is this easy to correct if it does happen and in your experience does it happen often? Thanks in advance! Cheers! To be honest, I never had any problem with back or front focusing with any lens. I do have a small problem with a K-7, but to overcome that problem I shoot with LV. It is a K-7 problem, all the other camera's any lens I own work perfect on them. What I do notice is, that more modern the camera, the better the results. Example: the 18-135 I used on my early Samsung GX-10 (K10d) gave very pleasing pictures, but on the KP this lens shines. It is such a fine lens, but it needs a good camera that can handle the IQ it delivers.