So, after reading all of the calibration hype I decided to give it a go. First up was my 18-140 and it appeared to have a significant back focus issue. I adjusted it from -20 to +20 with no adjustment in focus that I could tell. So I tried my 50mm......same deal. Now, let me go ahead and say that this wasn't the most precise calibration, as I was shooting at a 45 degree angle to a tape measure..........but I thought that I would be able to see a focus change between adjustments. I tried every distance from about 14 inches to 10 feet, same thing. I plan to print out or buy a more precise tool than a tape measure, but wanted to ask for your thoughts in the interim.
Lens calibration frustration
- Thread starter fmf
- Start date
Horoscope Fish
Senior Member
Don Kuykendall_RIP
RIP :(
The proper distance from most things I have read is 50 time the lens length. I generally use the longest part fo the zoom since it has the least DOF. So the 18-140 I would test at 140mm.
140mm X 50 = 7000mm or 22.96588 feet round off to 23 feet
Are you just looking in the viewfinder or are you loading it into the computer and looking at the focus there? Also if you are just shooting a tape measure what are you letting the auto focus, focus on?
With fine tuning a lens you have to be very precise and methodical. Anything else then you are just wasting your time and probably making it worse.
You can print out this chart and it does a pretty good job
GhettoCAL: A DIY Lens Calibration Tool for Microadjustment-Enabled DSLRs
Make sure to use matte or flat paper and not glossy
You can get self stick foam core at Office Depot to mount it all. Again be a precise as you can in printing and setting all this up for the best results.
The last thing is to have very good bright lighting. Any thing else is drive you crazy and not give you good results.
I tried many systems and methods and was never satisfied with any of them till I bought a software based system
FoCal Pro - Reikan FoCal Automatic Lens Calibration SoftwareReikan FoCal Automatic Lens Calibration Software
140mm X 50 = 7000mm or 22.96588 feet round off to 23 feet
Are you just looking in the viewfinder or are you loading it into the computer and looking at the focus there? Also if you are just shooting a tape measure what are you letting the auto focus, focus on?
With fine tuning a lens you have to be very precise and methodical. Anything else then you are just wasting your time and probably making it worse.
You can print out this chart and it does a pretty good job
GhettoCAL: A DIY Lens Calibration Tool for Microadjustment-Enabled DSLRs
Make sure to use matte or flat paper and not glossy
You can get self stick foam core at Office Depot to mount it all. Again be a precise as you can in printing and setting all this up for the best results.
The last thing is to have very good bright lighting. Any thing else is drive you crazy and not give you good results.
I tried many systems and methods and was never satisfied with any of them till I bought a software based system
FoCal Pro - Reikan FoCal Automatic Lens Calibration SoftwareReikan FoCal Automatic Lens Calibration Software
Yes I did. However, I'm pretty sure the problem is in my setup. I just moved the camera 90 degrees and it looks like it has a front focus issue. Move it back to the original spot, it looks like it has a back focus issue. So I will go at this a more precise way tomorrow I guess.
Don Kuykendall_RIP
RIP :(
This is the problem I have with fine tuning my lenses. making stuff worse. I don't have any 2000 dollar high end lenses to fine tune.
Don Kuykendall_RIP
RIP :(
I have fine tuned my wife's 18-200 for her D7000 and My 18-140 for my D7100 and have been happy with the results on both. My 70-300 still needs a little work I think. I plan on tuning it again at 70mm, 180mm and again at 300 and then averaging the results and using that as my setting.
I truly think there is no perfect method but doing nothing generally is not optimum. I remember someone recently here said they tuned at several zooms and averaged them. I am not quite sure who it was because I am old and the memory is going fast but it sounded like it might be a pretty good idea or at least worth a try.
I may try that method on my 70-300. Just what exactly was the problem on your 70-300 and how much better is it now and in what way? When you place a focus point on a target, (lets say on an otter's eye) is it now dead on?
Don Kuykendall_RIP
RIP :(
When I first started to shoot with it the focus was soft. Not bad but just not where I thought it should be. Most of the time now it is pretty close depending on what I am shooting. As you know there are so many factors involved that sometime it is difficult to pin done exactly what is going on. At full zoom it is pretty much dead on. it is when I try to shoot something close at full zoom that is more the problem. They tend to be a little soft. It may just be that is the way it is but I think that if my split the difference in the long and the short both will be in an acceptable range. WE will see once I get a little time to play with it. Been having to learn how to shoot with multiple lighting again. Been so long since I shot that way that it is all new to me again.
Thanks for that explanation Don! I have the same problem at full zoom close up as well. I always thought that since I'm at full zoom(300mm) and so close that camera shake was the problem. Even at 1/1600th.
I'm off next week, and when I get back from Okefenokee, I will devote a whole day to it.
Did you do any tuning with your 24-120 yet?
Well camera shake will be a factor at 1/160th if you are zoomed out to 300mm ...
General rule of thumb is the shutter speed should match or exceed the lens focal length so at 300mm it needs to be 1/320th or higher to eliminate hand shaking
Hehe sorry my dodgy eyes read 160th !!
Don Kuykendall_RIP
RIP :(
We had a private boat tour at Okefenokee last year. We went early in the year (Spring Break) so it was a little to early in the year so we id not see to many gators. We did see a few though. https://www.facebook.com/dkuykendall/media_set?set=a.10203763168148256.1073741895.1490357588&type=3
The 24-120 was tuned the day I got it. I shot a few first just to make sure that everything worked properly and then looked at the photos and then tuned. It was fairly close out of the box if I remember correctly....Just went to check. It is at a +4 so off a little. 4 points on these lenses make more difference than I would have thought.