back alley
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first of all, it's a zeiss lens made by cosina, not by cv.
and, i believe the discussion is about the 'look' of a lens, not comparing charts.
i happen to like the look of this lens.
and, i believe the discussion is about the 'look' of a lens, not comparing charts.
i happen to like the look of this lens.
raid
Dad Photographer
Roland,
How about my WWII era Kodak 363mm 1.66 lens? Can you match it with a CV lens? It weighs a ton, so it has to be a better lens than you CV lens!
How about my WWII era Kodak 363mm 1.66 lens? Can you match it with a CV lens? It weighs a ton, so it has to be a better lens than you CV lens!
Trius
Waiting on Maitani
Raid, can you do a thorough bokeh test of the Kodak 363 for us? Make sure you have both early and late production samples, along with all the coating iterations.
Huh? If only one in five to ten CV lenses were any good, Cosina would have been out of business long ago
The ZM Biogon 28/2.8 is a very nice lens, but I recently sold mine and replaced it with an LTM mount CV Skopar 28/3.5. The great results I kept getting with my SC mount CV Skopar 28/3.5 (first and only sample of this lens) was the deciding factor for me (some samples in this thread). No regrets so far and it was also nice to have an extra $300 in my pocket to spend on other goodies.
jky
Well-known
back alley
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jky
Well-known
I've been happy with the f2.0 Ultron, but I loved, and much prefer, the images with the Biogon. The Ultron will most likely be up in the classifieds soon....
Turtle
Mentor
Some sweeping statements here. Some evidently prefer the biogon to the hex so I guess opinions vary on your first statement.
On the subject of CV QC, some models seem more susceptible to variation than others. The 28 3.5 seems to be less variable than the 21/25 or even the 28 1.9 and 35 1.7. Like the 28 3.5, the 35 2.5 also seems to deliver the goods more often than not. I struck gold on my first 35 2,5 PII but had issues with a 21P, which would appear statistically about right judging by the higher apparent incidence of reports of decentering with the 21/25. making those lenses would appear more difficult than the modest 35 2.5.
On the 25, sean reid tested about for or so CV 25s and all had one corner (or more) noticeably worse than the others. Similar issues were noted with the 21. Other models have fared far better.
fuwen
Well-known
Not sure if I have made myself misunderstood. What I am trying to say is knowing and heard so much good things about the ZM 25/2.8 (including a very impressive MTF and the high resolution test done by Zeiss on a hot air balloon), I have decided to stick to the ZM 28/2.8 because I can use it without external finder on my Rollei 35RF. But now I have a R4M so I can actually happily use a ZM 25/2.8 on it. Very tempting but till now I have still decided to stick to ZM 28/2.8. Otherwise I will have both the 25/2.8 and 28/2.8 and need to decide which to bring out or both. I like 28mm focal length so dun think I will give it up and keep the 25mm.
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Turtle
Mentor
HERESY! I don't understand this approach when you could get the correct answer from a forum poll.
back alley
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polls are good fun...
ferider
Mentor
As I understood, the discussion was on "look" vs. charts, not one or the other. And again, even though the Biogon underperforms when compared to Leica and other lenses, for both M8 and RD the Biogon charts are actually very good, outperforming both sensors. I did feel that was a very interesting subject.
A chart is just that: a summary of measurements, defined as accurately as possible. As we've seen in Raid's most recent lens test, a few rolls of almost identical pictures of your kids can be charted as well and used as a metric. The interpretation and the emotions you put in reading metrics are your own.
You can of course decide to ignore tests and charts alltogether. And rather worry about using chrome lenses on a chrome body, or lens kits including only one brand, etc. etc. I for one prefer comparative data, and rather more than less, independent of what's fashionable. And decide on a case by case base what they mean.
Compliments to Zeiss and Leica for publishing MTF charts in the first place. I never understood why CV doesn't do the same.
Roland.
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fuwen
Well-known
Frankly speaking for most of us I believe the MTF is of little use for most practical purposes. That being said, I think the most usefull one will be the distorsion chart (which technically speaking is not a MTF chart) but even that at 4% distortion the lens should be still good to use other than to meet very critical requirements for architechture shots.
If CV were to publish their MTFs then they may appear to be inferior to Zeiss and Leica then no marketing advantages for them. But then again CV lenses (and to me all other lenses) for practical purposes should be good enough already, characters of the lenses aside. Not sure for Leica, we know that Zeiss MTFs are production MTFs taking into account variation in quality. It seems the MTFs published by other make (like Canon that I have seen) are apparently theorical curves and in fact are much better than Zeiss ones!
back alley
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roland, i am happy that you like charts and researched information, more power to you. i am guessing that your profession might include this sort of info as well and that it's very useful for you.
for me, it might as well be in another language for all i can gather from it.
my over reaction comes from inane and ridiculous comments, like you need to try 10 to find one good one, comments made to be inflammatory and insulting.
i think in the future i will just ban folks who try to provoke others, rather than become too emotionally involved, which is one of my traits and helps in my work.
Trius
Waiting on Maitani
Can't we all just take pictures?
Dan States
Established
Before you start interpreting MTF graphs I do suggest reading the excellent primer on the subject on the Zeiss website.
Yes, the Zeiss Biogon MTF APPEARS to indicate poor off center performance, but in fact does not.
The drop in measured contrast in this case is due to the field curvature in the Biogon. It is atypical because it bends back toward the focal plane instead of away. The practical effect however is actually (usually) to the benefit of street shooters as it allows the closest corners (the ground?) to be critically sharp. You can see the effect on distant objects at the corners of the frame if you look closely, but stopped down to F5.6 or smaller it's not really visible in general photography.
The lens has great control of astigmatism and maintains contrast above 40% even at 40lppm. Folks, Zeiss has been making lenses for some time now, they won't release a clunker...they don't have to.
Best wishes
Dan
Yes, the Zeiss Biogon MTF APPEARS to indicate poor off center performance, but in fact does not.
The drop in measured contrast in this case is due to the field curvature in the Biogon. It is atypical because it bends back toward the focal plane instead of away. The practical effect however is actually (usually) to the benefit of street shooters as it allows the closest corners (the ground?) to be critically sharp. You can see the effect on distant objects at the corners of the frame if you look closely, but stopped down to F5.6 or smaller it's not really visible in general photography.
The lens has great control of astigmatism and maintains contrast above 40% even at 40lppm. Folks, Zeiss has been making lenses for some time now, they won't release a clunker...they don't have to.
Best wishes
Dan
Turtle
Mentor
ignorance and deliberate provocation are not the same thing. I found it funny that after testing the CV 35 2.5 against the F2 biogon, well known for good smooth bokeh, the CV was virtually indistinguishable at the same apertures. I had no clue without my notes, but after looking at two rolls deliberately shot with the most heinous bokeh conditions in mind, I could see a very slightly (and I mean very) smoother bokeh on the Zeiss. After reading so many emphatic statements that this CV lens' bokeh is crap from Leicaphiles I was a very happy camper. You can't beat real information!
Alberti
Well-known
Hi Sirius, I have had such green flares when I did not use an IR filter - the M8 sensor is sensitive in that wavelength area. For instance, a candle that is in the picture, will 'double' itself, and you can see it reversed close by. So somewhere (maybe on a coating) the IR bounces back and forth in a lens.
I think this also happens in your picture (which has a nice 'daylight' atmosphere).
Could that be the case? Then the lamps would not be fluorescents but rather tungsten lamps.
The most hilarious example I ever saw (on LFI) was the headlights of a car that appeared as a set of 'tooth' in a face. One has to remain serious when one sees that of course. . .
alberti
Alberti
Well-known
Fuwen, This is maybe in line with how I was thinking: the 25 has a different character (in sharpness and the whole rendering) but why don't I just buy one too, it looks like a wide 28mm on the viewfinder anyway, so can be intermixed.
(My 25mm Color Skopar LTM is also on a 28mm flange). So then I can decide what suits the opportunity best. That all for the price of an Elmar.
Note I do not use the 25 mm often. But hey, I decided to stick to the VC as back-up for large (daylight/outdoor/architecture) pictures. Both money and that lens stay in my pocket!
alberti