jerryc41 Loc: Catskill Mts of NY

Bingo!

Jerry G Loc: Waterford, Michigan and Florida

Does anyone remember when photography magazines would test new lenses.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

IMHO, the OP SHSO MFT.

CO

I did some research into MTF charts when I put together a PowerPoint presentation for my camera club once. I don't remember anything about specific wavelengths being used. I think the full spectrum of light was used. These are two of the slides I put in the presentation. Look at the bottom slide. They are measuring the contrast between white and black line pairs. The line pairs become more dense going from left to right. It becomes more difficult for the lens to distinguish the difference between the white and black lines. The lens is "seeing" less contrast between the lines. The upper row is the test pattern. The second row is what the lens is seeing. You can see how there is a lot of contrast at the left end less contrast at the right end.

In the upper chart, the horizontal axis is the distance in millimeters starting at the center of the lens. The lines on the chart are dropping because the lens cannot resolve the lines pairs as well towards the edges of the lens.

bamfordr Loc: Campbell CA

And, of course, there is LSMFT

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

MTF is not the same as MFT -

lmTrying Loc: WV Northern Panhandle

Good one, Bill. As a John Deere parts man, I liked to screw with techs in Iowa who always used acronyms in their printed communications.
Got to have some fun along the way. Learned that from M.A.S.H.

lmTrying Loc: WV Northern Panhandle

lololol
Remembered the letters, just had to think a couple of seconds for what they stood.

StanRP Loc: Ontario Canada

Hi,

This is a link to an article on MTF on the NIKON website.

http://www.nikonusa.com/en/learn-and-explore/a/products-and-innovation/what-is-a-lens-mtf-chart-how-do-i-read-it.html

StanRP

jerryc41 Loc: Catskill Mts of NY

And let's not forget MTBF.

http://whatis.techtarget.com/definition/MTBF-mean-time-between-failures

lmTrying Loc: WV Northern Panhandle

After reading the link, I'd call it Mean Time Before Failure. Because after Failure there usually is no return to service.

Morning Star Loc: West coast, North of the 49th N.

Even if he had spelled out "Modulation Transfer Function" it still doesn't mean a thing to me ;-)
Best I can tell, it's important when you buy a lens, but once you have lens, you're stuck with it?
Since I don't understand it, I don't worry about it.
(Don't get me wrong, that's NOT my attitude for everything, there are other things that I will research and ask questions about till I DO understand them!)

jerryc41 Loc: Catskill Mts of NY

For a long term use item, wouldn't they just repair it and continuing using it?

More info -
http://world-class-manufacturing.com/KPI/mtbf.html

aflundi Loc: Albuquerque, NM

OP here. Sorry for not spelling out MTF. I figured it is so fundamental to photography, it would be virtually universally known, and if a person didn't know what an MTF was, they would exercise a bit of restraint and read to learn rather than feel compelled to waste bandwidth and give a useless answer. Sorry. My bad. So, here it is: MTF == Modulation Transfer Function.

Thanks to those that provided links to basic explanations for those that didn't know what an MTF was. Maybe it'll reduce the noise next time an MTF comes up. (or not. )

So, as a reminder, the question was whether a vendor might calculate, or if you are Zeiss, actually measure, the MTF using a single wavelength or a narrow band, versus a flat, white-light, continuous spectrum for the calculations or measurement.

I think this would be important to know because if something other than a full flat spectrum is used, the results would look deceptively good, and might well be meaningless. It might also mean that the interpretation of an MTF might well be completely different than the usual.

Virtually every time MTFs are explained, a caveat is thrown in that MTFs from different vendors can't be compared. Is this possibly why? It might explain why Canon MTFs from Canon often look much worse than those from other vendors. Is it possible that Canon is the only one doing an honest flat white spectrum calculation?

Lens Rentals has an optical tool for measuring MTFs. Do they use a flat white light source, or a narrow-band laser? Anyone here have any insights?

rmalarz Loc: Tempe, Arizona

Or possibly LSMFT.
--Bob