Home · Register · Search · View Winners · Software · Hosting · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username   Password

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Canon Forum | Join Upload & Sell

1
       2       end
  

Setting Up an Optical Testing Station
  
 
Fred Miranda
Offline
Admin
Upload & Sell: On
p.1 #1 · p.1 #1 · Setting Up an Optical Testing Station


Setting Up an Optical Testing Station
Roger at LensRentals.com posted a detailed article on how to set-up an optical testing station. If you suspect your lens is tilted, this could be worth your time.

You may download the ISO 12233 chart from here.

Here is an excerpt:

"Weíve been testing exactly this way for several years, identifying 60 to 70 lenses a month as decentered. We retest all of those on an optical bench and rarely find one that was actually OK. In other words, the test is nearly 100% specific. If it says a lens is decentered, itís almost certainly decentered."

Read entire article



Feb 20, 2014 at 07:57 PM
jcolwell
Offline
• • • • • • •
Upload & Sell: On
p.1 #2 · p.1 #2 · Setting Up an Optical Testing Station


Thanks Roger.


Feb 20, 2014 at 08:03 PM
dhachey
Offline
• •
Upload & Sell: On
p.1 #3 · p.1 #3 · Setting Up an Optical Testing Station


Very useful article. So Roger, when you find a decentered lens, what do you do? Fix it yourself or send it off to Canon? If my estimate is right, about 1% of your lenses come back out of whack each month. That's much better than I would expect.


Feb 20, 2014 at 09:12 PM
RCicala
Offline
• • • •
Upload & Sell: On
p.1 #4 · p.1 #4 · Setting Up an Optical Testing Station


It depends on the lens. Some are quick and easy to recenter (50mm f/1.2 for example) and we do those ourselves. The rest get sent to Canon. After Canon has their shot, we end up redoing a number of those ourselves. Canon is great getting the center sharp, but they don't do very well cleaning up the corners on certain lenses.

In the third part I'm going to use some lenses we've recentered as examples (70-200 f/2.8, 50 f/1.2, 16-35 f/2.8) just to show how the test looks before and after, and did Imatest before and after to give a correlation. It will probably be over the weekend before I get that posted, though.



Feb 20, 2014 at 09:20 PM
andyjaggy82
Offline
• • •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Setting Up an Optical Testing Station


You guys could make a killing just testing and fixing people's decentered lenses.


Feb 20, 2014 at 10:32 PM
dhachey
Offline
• •
Upload & Sell: On
p.1 #6 · p.1 #6 · Setting Up an Optical Testing Station


Thanks Roger. I look forward to part two. I' do a bit of optical work in my day job, but most of the time I push ions around the vacuum chamber of mass spectrometers, so I'm not really afraid to take things apart. Most of the time I even put them back together correctly. I really appreciate the hard work you and your team devote to service, I know how much effort goes into it.

Cheers, ...Dave



Feb 20, 2014 at 10:36 PM
RCicala
Offline
• • • •
Upload & Sell: On
p.1 #7 · p.1 #7 · Setting Up an Optical Testing Station


andyjaggy82 wrote:
You guys could make a killing just testing and fixing people's decentered lenses.


Not the way we do it now. We're willing to spend 4 hours recentering a messed up lens because the alternative is to write it off and part it out. I'd have to charge a whole lot to make a killing adjusting two lenses a day, though, especially when you add in the cost of parts, testing equipment, and the fact that we can't always get some adjusted.

I've actually spent most of the last year researching testing equipment and have spent a fairly large fortune ordering some of that stuff. If some of it pans out to remove some of the trial and error from the process, then maybe it will become quick enough to be worthwhile. Part of me thinks "if it was such a great idea someone would have already done it".

But then again, years ago people told me "if renting lenses online was such a great idea, somebody would have already done it". Actually, most people weren't that polite



Feb 20, 2014 at 10:45 PM
Pixel Perfect
Online
• • • • • •
Upload & Sell: On
p.1 #8 · p.1 #8 · Setting Up an Optical Testing Station


I know Canon Australia has an amazing high tech lens testing/alignment machine that at least last year was the only one and does cost a bomb.


Feb 20, 2014 at 11:15 PM
Wildcats_Fans
Offline
• • •
Upload & Sell: On
p.1 #9 · p.1 #9 · Setting Up an Optical Testing Station


Great article


Feb 20, 2014 at 11:29 PM
Fred Miranda
Offline
Admin
Upload & Sell: On
p.1 #10 · p.1 #10 · Setting Up an Optical Testing Station


Pixel Perfect wrote:
I know Canon Australia has an amazing high tech lens testing/alignment machine that at least last year was the only one and does cost a bomb.


Canon Irvine too. I visited the facility and was impressed.



Feb 20, 2014 at 11:34 PM
 

Search in Used Dept. 



Cgb628
Offline

Upload & Sell: On
p.1 #11 · p.1 #11 · Setting Up an Optical Testing Station


RCicala wrote:
But then again, years ago people told me "if renting lenses online was such a great idea, somebody would have already done it". Actually, most people weren't that polite


The King of Lens Rentals proudly wears his crown now, though.



Feb 21, 2014 at 07:51 AM
Richard Nye
Offline
• • • •
Upload & Sell: On
p.1 #12 · p.1 #12 · Setting Up an Optical Testing Station


I learned a lot from the blog, thanks for helping us Roger!

When I test my lenses, this is what I do to get my sensor parallel to the test chart:

I have a mirror that I can mount on a light stand (or second tripod if you have one). I move the camera (height, rotation, elevation, etc.) until I can see myself in the mirror when I look through live view. That way I know the mirror and sensor are parallel. I have a small test target I then tape flat to the mirror.

For a larger test chart like this, you could hang the mirror by string over the center of the test chart so the mirror is flat against the test chart.



Feb 21, 2014 at 03:35 PM
jeraldcook
Offline
• • •
Upload & Sell: On
p.1 #13 · p.1 #13 · Setting Up an Optical Testing Station


Any idea if it matters how the chart is printed? Inkjet vs. laser or if paper type is important?


Feb 21, 2014 at 03:55 PM
RCicala
Offline
• • • •
Upload & Sell: On
p.1 #14 · p.1 #14 · Setting Up an Optical Testing Station


Richard, that might be enough, but I'd double check the first chart image in photoshop to make sure it's good. We have tried that setup for Imatest and it's not nearly accurate enough -- but Imatest requires a lot more accuracy than this method (0.1 degree in Imatest is enough to affect the results).

Jerald, I've found a high quality inkjet print is good enough for this technique, although you'll definitely see a resolution difference between that and a linotype printed professional chart. A couple of people have emailed me that they've had large charts printed by services from the PDF available online and were happy with it.

Matte or semi-gloss paper, if you have spot lighting, is a lot more consistent. If you have a setup with smooth lighting from softboxes, glossy paper may give you a bit more resolution.



Feb 21, 2014 at 05:16 PM
Alek Komarnits
Offline
• • •
Upload & Sell: Off
p.1 #15 · p.1 #15 · Setting Up an Optical Testing Station


I had already read this (Roger's Blog is a must-read!) but just thought I'd add a ditto to what others said about yet another great writeup by Roger and the LensRental Team ...


Feb 21, 2014 at 05:55 PM
IndyFab
Offline
• • •
Upload & Sell: On
p.1 #16 · p.1 #16 · Setting Up an Optical Testing Station


Fred Miranda wrote:
Canon Irvine too. I visited the facility and was impressed.


So does that also mean Virgina and NJ also has one ?



Feb 21, 2014 at 06:07 PM
MarshallG
Offline

Upload & Sell: Off
p.1 #17 · p.1 #17 · Setting Up an Optical Testing Station


Roger, I first would like to thank you for sharing this wonderful information with us. You are very much appreciated and beloved by many photographers!

I have a question about "squaring" the camera to the target. I read elsewhere that an easy method is to tape a mirror over the center of the target and put the camera in LiveView. This lets you see the opened lens and adjust the camera until it is "square" with the target, because the opened lens won't appear as a full circle unless it is correctly square with the target. I've never tried this, but I've wondered if you have, and, if so, do you think the method works?



Feb 22, 2014 at 07:08 PM
RCicala
Offline
• • • •
Upload & Sell: On
p.1 #18 · p.1 #18 · Setting Up an Optical Testing Station


Marshall, we tried that technique when we first started using Imatest. It wasn't accurate enough for Imatest so we haven't revisited it. It might be OK for this technique which doesn't require quite that degree of accuracy. (In Imatest, being off by 0.1 degrees is enough to mess up the results).

The mirror technique would probably be accurate enough for this, especially at longer focal lengths, but I would double check a picture in Photoshop just to be certain it's fairly close. A degree or so is OK for this technique.



Feb 22, 2014 at 09:06 PM
RCicala
Offline
• • • •
Upload & Sell: On
p.1 #19 · p.1 #19 · Setting Up an Optical Testing Station


If anyone's interested, I have some examples posted now:

http://www.lensrentals.com/blog/2014/02/examples-using-an-optical-testing-station



Feb 22, 2014 at 09:56 PM
Alek Komarnits
Offline
• • •
Upload & Sell: Off
p.1 #20 · p.1 #20 · Setting Up an Optical Testing Station


I commented on the blog post ... but gotta love Roger's humor! ;-)

"Most people who try optical adjustment at home convert a below average lens into a totally useless lens."



Feb 22, 2014 at 10:09 PM
1
       2       end




FM Forums | Canon Forum | Join Upload & Sell

1
       2       end
    
 

You are not logged in. Login or Register

Username   Password    Retrive password