Ugly Hedgehog - Photography Forum
Home Active Topics Newest Pictures Search Login Register
Main Photography Discussion
Fine Tuning a lens
Page 1 of 3 next> last>>
Sep 20, 2019 12:35:34   #
mittenjane
 
I recently upgraded to a "new to me" camera that has the lens fine tuning feature. I have read the instructions on how to, but wondering A.) if it is necessary and B.) is there a process I should follow to get the tuning correct?

Any assistance is appreciated.

Reply
Sep 20, 2019 12:37:24   #
CHG_CANON Loc: the Windy City
 
Do you have any lenses that don't seem sharp on this camera? Do you shoot your lenses wide open, particularly the f/2.8 and wider lenses?

Reply
Sep 20, 2019 12:41:12   #
mittenjane
 
I try not to shoot wide open - usually 3.5 as I am usually taking pics of kids and really need a greater DOF. Sometimes yes they are less than sharp but sometimes seem tack sharp. Haven't used the camera on a tripod so could be operator error.

Reply
 
 
Sep 20, 2019 12:42:30   #
Bob Mevis Loc: Plymouth, Indiana
 
CHG_CANON wrote:
Do you have any lenses that don't seem sharp on this camera? Do you shoot your lenses wide open, particularly the f/2.8 and wider lenses?


First do what CHG_CANON SAYS. If yes, download a focus test chart. Follow the directions for use. Mount your camera on a tripod and use a remote or use your cameras self timer and take a pic with each of your lenses. It's a good idea to do more than 1 test with each lens. IMHO.

Reply
Sep 20, 2019 12:50:52   #
CHG_CANON Loc: the Windy City
 
Bob Mevis wrote:
First do what CHG_CANON SAYS. If yes, download a focus test chart. Follow the directions for use. Mount your camera on a tripod and use a remote or use your cameras self timer and take a pic with each of your lenses. It's a good idea to do more than 1 test with each lens. IMHO.


I didn't "say" to do anything. If I had made a suggestion, I say to work on shooting technique rather than fine-tuning. I'd also worry about fine-tuning my primes and not my zooms. Just because a camera has a feature, doesn't mean that one must use it, particularly when it's more likely to cause problems (or do nothing) than to lead to a noticeable improvement. But, that's just me.

Reply
Sep 20, 2019 13:12:11   #
Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
 
mittenjane wrote:
I recently upgraded to a "new to me" camera that has the lens fine tuning feature. I have read the instructions on how to, but wondering A.) if it is necessary and B.) is there a process I should follow to get the tuning correct?

Any assistance is appreciated.


You only need to mess with the fine tuning tool in order to establish whether the camera or the lens is at fault.

If all other lenses are fine but one lens is off, then there is a good chance the lens needs to be adjusted. You can confirm this if you have another body to test the lens on.

If a lens is good on all other bodies but not great on one body, then the body is likely at fault.

Either way, the tool in the camera is a simple focus offset, which affects the focusing at all distances, and if you have a zoom lens, at all focal lengths. It's a ham-handed approach, and not intended to be a permanent fix. Focus performance varies with distance, and with zoom lenses it also varies with focal length. A lens may nail the focus at the minimum focus distance but front focus at 10 ft and back focus at 30 ft. There is no way a camera-based fine focus adjustment can handle that. Also, the AF sensor could be slightly off, where it is not precisely where the little box in the viewfinder says it is. This can look like front focusing if it is lower than the box, or back focusing if it is higher than the box.

The camera mfgr's have software and the ability to make physical adjustments to ensure the camera behaves within specification. I've got a bunch of lenses from multiple manufacturers that are accurate over a wide range of camera bodies, and none of the bodies have any fine tuning in effect.

Reply
Sep 20, 2019 16:44:17   #
CO
 
First determine if the camera and lens combination is front or back focusing. I use the DataColor SpyderLensCal to check. Some people use the Reikan FoCal Pro 2 software. It's probably the most sophisticated method for checking.

Since you say that some of your photos are less than sharp and others are tack sharp, it might be camera shake that is causing blur. Look at the metadata of those photos to see what the shutter speeds were. Also, if you have all focus points active, the camera's autofocus points could be landing on something other than your main subject.

If you have a Nikon, you can load the photo into Nikon View NX-i or Capture NXD and turn on "Show Focus Points". It will show exactly where the focus point(s) landed.

Reply
 
 
Sep 20, 2019 17:03:31   #
CHG_CANON Loc: the Windy City
 
Consider this idea:

Success is the photographer. Failure is the equipment.

Do you believe your technique is perfect and any / all failures to obtain 100% tack-sharp images is an issue with the equipment? If you do, here are two links that show how to use a tool and carefully set-up your tripod and ruler for very precise testing over a few millimeters to adjust your lens.

https://www.lensrentals.com/blog/2016/01/how-to-use-af-microadjustment-on-your-camera/
https://photographylife.com/how-to-calibrate-lenses

What I couldn't find is before / after examples to give a sense of the issues that exhibit opportunities to focus-tune. If you had a problem lens / camera combination, it would be fairly consistent for a specific lens; of course, assuming the photographer is not the root cause.

Looking at the AF point at 100% zoom on your large high-definition monitor is a good way to judge along with the shooting parameters. Say you had an image where the AF point was on the eye of a bird that mostly fills the frame. And yet, the focus is very sharp not on the eye but obviously in a plane of focus slightly closer or further back (i.e., front- or back-focusing). If your images give you a consistent issue using autofocus and a single AF point, maybe you'd experiment with the process in the links above. You'd see the same thing, the focus on the ruler is not at the 0-mark; but rather, slightly in front or back and slightly adjusting the camera for this lens will correct this issue.

Reply
Sep 20, 2019 18:00:00   #
travisdeland Loc: deland, FL
 
here's a link to a "how to" guide that canon put out on this subject-it's applicable to any camera capable of autofocus micro adjustment:

https://www.dropbox.com/s/ewh57wqs8lxgiy2/AF_MicroAdjustGuide_desktop.pdf?dl=0

Reply
Sep 20, 2019 20:05:58   #
mittenjane
 
Thanks everyone for your comments. Honestly I think it is just me getting used to this heavier camera. I downloaded and printed a focus sheet and using my tripod and remote - the photos were fine. Just need to work on my technique

Reply
Sep 20, 2019 22:11:33   #
CO
 
I don't see how a flat target can show anything about if the camera and lens is back or front focusing. I think the slanted ruler type target or the Reikan FoCal software are probably the best. I was testing my Nikon 16-85mm lens here. I can see by the slanted ruler that the zero is in best focus. That's ideal.


(Download)

Reply
 
 
Sep 20, 2019 22:30:53   #
Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
 
CO wrote:
I don't see how a flat target can show anything about if the camera and lens is back or front focusing. I think the slanted ruler type target or the Reikan FoCal software are probably the best. I was testing my Nikon 16-85mm lens here. I can see by the slanted ruler that the zero is in best focus. That's ideal.



Reply
Sep 20, 2019 22:55:54   #
CO
 
CHG_CANON wrote:
Consider this idea:

Success is the photographer. Failure is the equipment.

Do you believe your technique is perfect and any / all failures to obtain 100% tack-sharp images is an issue with the equipment? If you do, here are two links that show how to use a tool and carefully set-up your tripod and ruler for very precise testing over a few millimeters to adjust your lens.

https://www.lensrentals.com/blog/2016/01/how-to-use-af-microadjustment-on-your-camera/
https://photographylife.com/how-to-calibrate-lenses

What I couldn't find is before / after examples to give a sense of the issues that exhibit opportunities to focus-tune. If you had a problem lens / camera combination, it would be fairly consistent for a specific lens; of course, assuming the photographer is not the root cause.

Looking at the AF point at 100% zoom on your large high-definition monitor is a good way to judge along with the shooting parameters. Say you had an image where the AF point was on the eye of a bird that mostly fills the frame. And yet, the focus is very sharp not on the eye but obviously in a plane of focus slightly closer or further back (i.e., front- or back-focusing). If your images give you a consistent issue using autofocus and a single AF point, maybe you'd experiment with the process in the links above. You'd see the same thing, the focus on the ruler is not at the 0-mark; but rather, slightly in front or back and slightly adjusting the camera for this lens will correct this issue.
Consider this idea: br br Success is the photogra... (show quote)


Good article. They're using a LensAlign but have also made their own slanted ruler target.

Reply
Sep 20, 2019 23:56:28   #
RWR Loc: La Mesa, CA
 
mittenjane wrote:
... using my tripod and remote -

That’s the key to sharp photos. And use the focusing screen for its intended purpose - if the image is sharp there, it will be sharp on the sensor.

Reply
Sep 21, 2019 05:33:08   #
Architect1776 Loc: In my mind
 
mittenjane wrote:
I recently upgraded to a "new to me" camera that has the lens fine tuning feature. I have read the instructions on how to, but wondering A.) if it is necessary and B.) is there a process I should follow to get the tuning correct?

Any assistance is appreciated.


Play around with it.
I did that with my lenses and found all were best at the factory settings.
The fine tuning in both direction just made things worse.
A good quality lens and camera should not need fine tuning generally unless you see obvious errors consistently with your focus that cannot be attributed to any other cause.

Reply
Page 1 of 3 next> last>>
If you want to reply, then register here. Registration is free and your account is created instantly, so you can post right away.
Main Photography Discussion
UglyHedgehog.com - Forum
Copyright 2011-2024 Ugly Hedgehog, Inc.