RFF Optics Tests? Is this idea possible?

[raid]

You can get lens test reports on the newer design lensesbut it is difficult to get test results on specific lenses that were made many years ago. It is ven more difficult to see test results on similar lenses (old vs. new).

I will receive several lenses in the 85mm~105mm range for conducting a test. The owners fo the lenses pay for the mailing to me and I will pay fro sending the lenses back to them.

This gave me an idea ...

1. How about having the RFF first set up certain test criteria or instructions that are manageable and reasaonable.

2. Have the RFF decide on which type of lenses to test [by someone] and then have a place in one of the forums in which the test is announced so that volunteers can send in a lens to be tested.

3. Have a mechanism in which the postage money is voluntereed (maybe $1-$2 per interested RFF member] and send the money to the people who are offering their lenses to be tested and the person who will do the test (film, developing,mail). No profit will be made.

4. Post the results and crtiques by others in the RFF.



This would provide a unique set-up for custom designed tests of lenses of all ages and focal lengths.

What do you think about such an arrangement?


Regards,

Raid

 

[raid]

Roland,
What you suggest is easier to do but it could be introducing some confounding effect due to using different testers. On the other hand, there would be no mailing of lenses needed, and maybe the tests would be larger in scale too.

Maybe others will also support such a RFF project.

Regards,

Raid

 

[KoNickon]

This is an excellent idea. However, based on the comments I've seen on lens tests here before, there is a lot of difference of opinion about what makes for a "good" test. So agreeing on the protocols of the test will be the hardest part, I think. Just as an example, I think it might be a good idea, if possible, to test more than one sample of each lens so as to address the question of sample variation. I know others with more knowledge will weigh in on details like types of subject, lighting, apertures used, camera used, film used, type of metering, etc. Come to think of it, this could take as long as an industry standards organization to present its recommendations! But I remain optimistic.

 

[raid]

Nick:
If we are lucky, some sponsors may send us new lenses for tests.
The RFF can always have a poll if needed to decide on the test criteria.
The first step is alwys the most difficult one to take.

Raid

 

[jdos2]

I'd love an MTF of all my favorites- wide open, f/2, f/2.8, f/4, &c., all the way down. Perhaps even a "T-Stop" study of 'em as well...

 

[raid]

I'd love an MTF of all my favorites- wide open, f/2, f/2.8, f/4, &c., all the way down. Perhaps even a "T-Stop" study of 'em as well...

What is a T-stop study? Maybe you could clarify this. Thanks.

Regards,
Raid

 

[raid]

OK. My first criterion is a flare test. I would shoot somebody/something against the window light. I also like to compare the general rendition of a human face. This is what I mostly use my lenses for anyways.

Maybe you can give us the next criterion.

I bet, people will ask for a traditional sharpness test and also for bokeh test.
Someone might also ask for a color test to see different results, even though adjusting color has become easy after a scan.

Raid

 

[jdos2]

T-Stops are a measure of actual light transmission. Many older lenses (especially uncoated) will demonstrate less transmission than their f-stops would indicate, making "f/4" "t/5.6"
I'd like to see the graph for that based on distance from the optical center of the lens.

 

[raid]

Let's put together our "Dream Test" with all possible important factors. Then someone needs to help out by laying out the plan for doing such a test in a reasonable time frame. Is there any equipment needed in the test?

Raid

 

[NIKON KIU]

Hi Raid,
Posting the above propositions makes it more interesting than I imagined.
I suggest performing the basic line resolution test available here:
http://www.sinepatterns.com/i_Stdrds.htm
Or do a google search for lens resolution line test charts and do some readings....I personally vote for you as the designated lens tester(as I already did)😉
Kiu

 

[raid]

Thanks, Kiu. As if I have the time! I will do my next test first, and then we'll see.
My tests have been very basic in nature while others have done scientically designed tests.

Raid

 

[raid]

The Nikkor lens arrived in today's mail. If the other lenses arrive by this weekend, I can go ahead and do some testing.

I will try to include a bokeh test (for background look) and also a flare test. As for sharpness and contrast, I may just take photos of a well-lit subject.

Raid

 

[raid]

Hi Raid,
Posting the above propositions makes it more interesting than I imagined.
I suggest performing the basic line resolution test available here:
http://www.sinepatterns.com/i_Stdrds.htm
Or do a google search for lens resolution line test charts and do some readings....I personally vote for you as the designated lens tester(as I already did)😉
Kiu

Kiu,
How would I use these different charts?

Raid

 

[NIKON KIU]

Normally the target is to be mounted on a wall or like with the camera mounted on a tripod, test pictures would be taken at different distances and apertures say starting from minimum possible distance(for close focusing tests) and so on....
I personally would suggest the USAF (1951) test...after the test you learn the Line per milimeter performance by counting the number of lines on test photos.
This guy on ebay is selling similar for a bit less:
http://search.ebay.com/_W0QQsassZ1437justriteQQhtZ-1
I didn't realize the place in New York only sells them in volume.
Regads,
kiu

 

[raid]

Kiu,
This sounds rather complicated. If you are testing 8-10 lenses this way, you would be working for many long hours counting lines.

Raid

 

[ray_g]

I'm with Roland. The sharpness/resolution/contrast of a lens would be less important to me than the lens' "signature" unless I were printing in the darkroom.

 

[raid]

Roland,
I have noticed the lack of resonses myself. That's OK since I will do the tests for myself first. I also do not like MTF curves or charts since I am not trying to sell lenses; I just want to see how a lens renders a face or a scene in general.
I have Kiu's lens and I am waiting for the rest of the lenses 🙂

Raid

 

[raid]

Good. So I should get the lenses for the following weekend.

Raid

 

[egpj]

If I could make a suggestion. I know of one resource for scientific testing of optics.

http://www.edmundoptics.com/US/

There are some books and test charts that can be purchased off this website. I have to say though that this stuff is usually expensive. Some of my job is researching optics for Aerial sensor platforms. That is why I know about the Edmund Optics website. There is a book about MTF curves that is relatively inexpensive and then the test charts can probably be swung as well.

 

[raid]

Glann,
Thanks for the input. I may just shoot photos of my daughter and also some for bokeh but have no scientific measurements.

Regards,
Raid