I keep hearing that Zuiko lenses are some of the best ever made, and the photos I've seen posted seem nice, but the MTF graphs I've seen are abysmal -- not just one lens, but across the board. What makes them so much better in reality than in the lab?
bigreen505 wrote:
I keep hearing that Zuiko lenses are some of the best ever made, and the photos I've seen posted seem nice, but the MTF graphs I've seen are abysmal -- not just one lens, but across the board. What makes them so much better in reality than in the lab?
Have any other graphs you've seen included a 60 lp/mm line? Of course this must be weighed against a relatively finer fourthirds sensel pitch, but it still amounts to a more uniform performance throughout their lens lineup than, say, some N/C glass yields on 135. There aren't really any overpriced turkeys.
You know, I've never really paid much attention to the MTF graphs and this is the first I've heard of them being abysmal. Thank goodness for real life!
Paul
bigreen505 wrote:
I keep hearing that Zuiko lenses are some of the best ever made, and the photos I've seen posted seem nice, but the MTF graphs I've seen are abysmal -- not just one lens, but across the board. What makes them so much better in reality than in the lab?
Which Zuiko lenses are we talking about? OM or the new digital ones? The OM system never had manufacturer MTFs published as far as I know.
I can only assume bigreen is talking about the Oly OM MTFs and ratings over at old.photodo.com.
I've never heard a good explanation about why the results are so bad, but I never cared too much because I've used many OM lenses and they did not perform anything like those MTFs would indicate.
One thing to bear in mind when looking at these charts ... you are looking at 20 LPM & 60 LPM.
Compared to other's charts which may include those who use 10 LPM & 30 LPM, even 50 LPM, you are somewhat comparing oranges to tangerines. If you were to see the Oly's results at the lower LPM, they would undoubtedly show better MTF results on paper. This may be why in real world application they have a better reputation than the MTF (60 LPM especially) suggests. 60 LPM ... that is a tough act to pull off. I'd suggest finding other lense that have 60 LPM MTF charts and compare with them.
Not that I'm any expert in the matter, but I don't know of any other MTF charts that are reporting @ 20 LPM & 60 LPM.
The link below has the MTF for the Zeiss 100mm 2.0 Planar ... highly acclaimed.
Zeiss is reporting @ 10 LPM, 20, LPM & 40 LPM. If you look at its 20 LPM, you'll note that it has LOWER MTF scores than some of the Oly's that have been posted.
Another thing to notice is how tightly aligned the Oly's tangential & saggital lines correlate.
There are some excellent technical guru's in this Forum, who can better explain than I ... but I think Oly has presented their MTF's with a greater degree of scrutiny than others ... that is why at first glance, the MTF's 'look' worse than Oly's perform.
60 LPM is kind of like 'Pixel Peeping' @ 300% ... doesn't look quite as good compared to something else viewed @ 100% (a bit exagerated, but point is ...)
Another point is that if these lenses have been designed for the smaller 4/3 sensor size, the distance from center should be considered accordingly.
cogitech wrote:
I can only assume bigreen is talking about the Oly OM MTFs and ratings over at old.photodo.com.
I've never heard a good explanation about why the results are so bad, but I never cared too much because I've used many OM lenses and they did not perform anything like those MTFs would indicate.
Indeed I am as those are the only ones I've seen. I'm not suggesting these are overpriced, over-hyped turkeys, I'm looking at buying a couple. But I'm trying to understand why the reported MTFs are bottom of the barrel when the photos sing a different tune. They were tested a 10, 20, 40 lp. The 28/2 scores a 2.6.
bigreen505 wrote:
Indeed I am as those are the only ones I've seen. I'm not suggesting these are overpriced, over-hyped turkeys, I'm looking at buying a couple. But I'm trying to understand why the reported MTFs are bottom of the barrel when the photos sing a different tune. They were tested a 10, 20, 40 lp. The 28/2 scores a 2.6.
Any thoughts?
I can only assume some sort of imperfection in the testing methodology.
A better reference for comparing lenses is the old Modern Photography lens tests. They were very methodical in their approach. I have all the Oly lens tests ever published by them (and most of the ones that Pop Photo and others did) here:
Cogitech - I have to admit that is where my mind went too, but they were tested just like every other lens. If memory serves all the lenses were tested at infinity, so it is possible that affected the outcome.
RustyBug wrote:
One thing to bear in mind when looking at these charts ... you are looking at 20 LPM & 60 LPM.
Compared to other's charts which may include those who use 10 LPM & 30 LPM, even 50 LPM, you are somewhat comparing oranges to tangerines. If you were to see the Oly's results at the lower LPM, they would undoubtedly show better MTF results on paper. This may be why in real world application they have a better reputation than the MTF (60 LPM especially) suggests. 60 LPM ... that is a tough act to pull off. I'd suggest finding other lense that have 60 LPM MTF charts and compare with them.
Not that I'm any expert in the matter, but I don't know of any other MTF charts that are reporting @ 20 LPM & 60 LPM.....Show more →
The reason they use 20 lpm and 60 lpm with the 4/3rds sensor lenses is that is the rough equivalent of 10 lpm and 30 lpm on full frame lenses. The Zuiko 4/3'rds digital lenses are half-frame, with roughly half the image circle. To compare the resolution across the most tightly packed, half -size sensor you have to look at more tightly packed line pairs (20 and 60 lpm compared to 10 and 30 lpm). You can find a more technical explanation on the web.
For reference, Zeiss MTF's are for 10, 20 and 40 lpm.
Don't forget that Zeiss MTF's are measured ones and not theoretical ones like pretty much all MTF's of all other companies (Canon been the biggest example ).....
Keysersoze27 wrote:
Don't forget that Zeiss MTF's are measured ones and not theoretical ones like pretty much all MTF's of all other companies (Canon been the biggest example ).....
