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low_contrast VS high_contrast lenses
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PostPosted: Wed May 28, 2008 11:07 pm    Post subject: Reply with quote

Rob Leslie wrote:
Hi Orio. I think we agree !!!
You missed the bit
'In other words the some low contrast lenses will show a surprising amount of resolution when not faced by a high contrast test chart'
Or to put it another way low contrast lenses can have good resolution but often fail the old black and white line test.


Yes. Well, I rarely look at those tests, because I think that unless all lenses are tested by one person in a controlled environment and under equal conditions, it is very difficult to make them universally valid.
Even companies cheat with those tests, e.g. most companies publish as MTF graphs for their lenses, the result they got from their prototypes, not the results from actual lenses taken from the production line.

So what I basically do is to look at the images from those people like Veijo who are trustable and accurate enough to make believable samples - and make my opinion based on what I see from these real life tests - after all like you say, we buy lenses to photograph life, not rows of printed lines or book shelves.


PostPosted: Wed May 28, 2008 11:12 pm    Post subject: Reply with quote

[quote="Rob Leslie"]
estudleon
My apoligies as you say we all have to learn.
I have not studied lenses since 1965.
I choose to study photography. Optics was only part of it.
65 was about when I bought my Pentax SL.
1966 was when I started Art College.
Now is the time I'm still wondering how to do it right!!
As you say we have to learn and after 40 years I still haven't a clue.
I do know if you are using lenses on a camera you should consider the effect the camera and its recording medium has on them![/quote]

Pardon, Rob, I can't see in my notebook all your message.
I don't finish my photography studies, economics reasons did that I had to finish my lawyer career.
I love the optic theory, not the photography very much.
I'm a lenses collector. It's the pasion of my life.
And now yes, regards.


PostPosted: Wed May 28, 2008 11:14 pm    Post subject: Reply with quote

estudleon wrote:

I love the optic theory, not the photography very much.
I'm a lenses collector. It's the pasion of my life.


That's a good reason for being a lawyer. It gives you the money to cultivate this expensive hobby! Very Happy


PostPosted: Wed May 28, 2008 11:18 pm    Post subject: Reply with quote

ORIO
I NEED MORE MONEY!!!!!!!!!!!!
My wife think so (and me too)


PostPosted: Thu May 29, 2008 10:01 am    Post subject: Reply with quote

Quote:
The one thing that is possible to say, in my opinoin, is that while lenses with high resolvance and poor contrast can be effectively improved via software (as long as the low contrast is not really an openly visible flare), the opposite (lenses with low resolvance and high contrast) can also be improved (via sharpening), but not as satisfactorily. This because the action of increasing contrast in a digital image via histogram points editing is rather smooth, while the action of sharpening is often problematic, firstly because you can not create a content that is not there to start with, and secondly because sharpening via software can cause annoying artifacts even at low amounts.


I really really want a whiteboard or something to draw on! Because i mostly agree with the above, but not all of it, and could best explain what i mean by diagrams not words ...


PostPosted: Thu May 29, 2008 10:45 am    Post subject: Reply with quote

estudleon wrote:
ORIO
I NEED MORE MONEY!!!!!!!!!!!!
My wife think so (and me too)


OK, sell your lenses Twisted Evil Laughing


PostPosted: Thu May 29, 2008 1:50 pm    Post subject: Reply with quote

I checked back my files and it seems the contax file I used for the comparison was a modified one so all this theory was based on sand.
Sorry Embarassed


PostPosted: Thu May 29, 2008 1:51 pm    Post subject: Reply with quote

Heh heh, but it was fun and instructional nontheless


PostPosted: Thu May 29, 2008 2:24 pm    Post subject: Reply with quote

Orio
Never, never I will sell my lenses. I need much, very much money to buy
more lenses. Particular collector sell a summilux GOLD with GOLDEN IRIS (not in catalog) in $ 10.000. I will kill (to anybody) for this.


PostPosted: Thu May 29, 2008 2:59 pm    Post subject: Reply with quote

estudelon - how much are livers going for these days? Smile


PostPosted: Thu May 29, 2008 3:10 pm    Post subject: Reply with quote

Nesster
I really love to see my news lenses while listen to Maria Callas in Mozart's Il ratto dal seraglio.
I love do this and nobody will impede it to me, never. Embarassed Embarassed Laughing


PostPosted: Thu May 29, 2008 3:30 pm    Post subject: Reply with quote

[quote="ChrisLilley"][quote]The one thing that is possible to say, in my opinoin, is that while lenses with high resolvance and poor contrast can be effectively improved via software (as long as the low contrast is not really an openly visible flare), the opposite (lenses with low resolvance and high contrast) can also be improved (via sharpening), but not as satisfactorily.

i]really really[/i] want a whiteboard or something to draw on! Because i mostly agree with the above, but not all of it, and could best explain what i mean by diagrams not words ...[/quote]

Chrislilley
Are you agree with the first paragraph?
My problem is that I can't perceive the resolution power of the constrastiers lenses. Sometimes I have to assume this. Just the contrastiers things impede to me to see the delicates and thins lines. And with the less contrastier lenses I am very much exigent to judge the sharpness because [b]I see that lines[/b].


PostPosted: Sun Jun 15, 2008 1:05 pm    Post subject: Reply with quote

Sometimes Zeiss Contax lenses might be too high in contrast. For that situation I would pull out Zuiko lenses. In that kind of light they earn their "Japanese Leica" moniker. Speaking of dslr of course.