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A superfast normal on the G1

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Vivek

Guest
Here is the AA plus UV/IR cut filter of an E-410, the sensor dust shaker plate is visible on the photo as well and the fixed cover glass on the senor is inside.


Panasonic G1, Senko 25/0.95.

The material used for the AA filter is most likely LiNbO3 (lithium niobiate), plus there are layers of other materials. It is a complex piece of engineering. The sensor cover glass and the dust shaker glass could be "some" glass (unlikely BK-7). So, the total refractive index of these layers may or may not match the BK-7 of a Bolex RX prism.

This is the general scenario with all digital cameras and lenses (even the current ones as each model of the camera tends to have slightly different filter combinations).

The question you need to ask yourself is, is photography an exact science?

To me, the answer is no.

Mind you, I have and use(for special purposes) some the best lenses (perfect lenses to be precise) ever made. I can use a color corrected Printing Nikkor 95/2.8 for distortionless (0.0000% distortion) copy purposes, for example.

That lens was incidentally made for copying movie films.

To me, this "analysis" that movie camera lenses are ill suited for digital still photography by stringing partial information from various sources and coming here and dissing equipment, usage and the users gives clear indications of boredom.

This kind of "web analysis" isn't a bad pastime but I would think picking up a camera (Gemini or otherwise) and making use of it is a better way to kill the time.:)
 
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dcouzin

Guest
MODERATOR WARNING
there will be no insulting labguage.
Please respect other members
thanks
-bob
 
Last edited by a moderator:
V

Vivek

Guest
Correction noted (on the magnification). Yes, I can even show them off if you like. ;)

In fact, I have the 95/2.8N, 105/2.8N and the 150/2.8A (the last version) Printing Nikkors (the last two optimized for 1:1) or even a Repro Nikkor 85/1!:D

Perhaps you measured the distortion of the 95/2.8 Printing Nikkor. Neither my feeble tests not the Nikon literature I have claim that 0.02% distortion. :(

Although, the Printing Nikkors are corrected from 400-800nm light (thus qualifying to be APO), Nikon did not classify them as APO.

If you have suggested cheaper ones and some benefited out of that, that is a good deed, indeed (sorry, your external links, I can not access). [You should have suggested that to Nikon as well.]

If you have something positive to contribute, by all means do it and it will be appreciated. Otherwise, stop making characterizations.

Again, if you have something to show (pics), show them. I am not into this wordy duels and chest beating "i am an expert" deal.

I am reporting this to the mods as well.
 
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dcouzin

Guest
Revision of the moderator-deleted post.

The question you need to ask yourself is, is photography an exact science? To me, the answer is no. Mind you, I have and use(for special purposes) some the best lenses (perfect lenses to be precise) ever made. I can use a color corrected Printing Nikkor 95/2.8 for distortionless (0.0000% distortion) copy purposes, for example. That lens was incidentally made for copying movie films.
Funny that you mention a Printing-Nikkor lens. In 1978 got a small NEA grant for motion picture optical printing research and immediately blew $2600 of it on a Printing-Nikkor 105/2.8. That's the 1:1 lens in the series, and being fully symmetrical it is distortionless at 1:1. (Every fully symmetrical lens, even a single element, is distortionless at 1:1.) The Printing-Nikkor 95/2.8 you mention was designed for 2:1 and is not distortionless at 2:1. According to the Nikon literature it has 0.2% distortion at 2×. Every photographic lens is of course "color-corrected". Nikon described the Printing-Nikkor's as "apochromatic" in its first brochure.
I believe photography is an art which rests on much exact science. I've done serious work to help students and artists find simple lenses for their purposes. For example in Good cheap lens for 16mm optical printer (1986) I suggest a $100 lens to substitute for the (by then) $4600 Printing-Nikkor. This was based on sophisticated measures while being down to earth.
That old 1986 problem resembles this strand's problem. An inexpensive lens is desired for a certain imaging task where none is made. Seemingly inappropriate lenses are tried out with some pretty good results. Mounting the lenses is a little pain. What's missing from this strand is the application of any lens sharpness evaluation methods beyond looking at JPEGs with less than a million pixels.
A big difference between the 1986 problem and this strand's problem is that the former involved optical printing and the later involves picture taking. In optical printing the big analog woe was loss of sharpness from generation to generation. The sharpness demands on the optical printer lens were therefore extreme. What are the sharpness demands on the G1 picture taking lens?
 

m3photo

New member
Re: Pentax 110 lens on G1

Hey m3, do you want to tell us how you created the 110 adapter - I'm half way through mine.
I wouldn't go so far as say I "created" an adapter to be honest. I found a deal on E-Bay that included a 24mm and a 70mm lens with a non-functioning Pentax-110 body. I took the body apart and then stuck the lens mount onto a C-Mount adapter with black electrical tape. I find that if I pull the lens mount towards the camera whilst focusing (the tape doesn't make for a perfect flush mounting but suffices for the time being) and using focus magnification, infinity focus is certainly attainable with these little lenses - the church example is here to prove it. One might think what the purpose of mounting these on the G1 is, it's really down to being stealthy whilst in a street environment. A 140mm equivalent, or better still 238mm with the cutest 1.7 multiplier you ever saw, is way smaller and unobtrusive when photographing passers by on the other side of the pavement, for example.
I'll be buying the GF1 or similar to mount the 18mm Pentax-110 on it as a street shooter when I get round to it. I will then of course seek a more permanent lens mount as for the moment the sticky-tape/focus-magnification/pull back with two fingers route isn't exactly fast!
If anyone needs images of what I'm talking about I'll be glad to whip out my trusty G9 and take shots of the "set-up" for y'all :D
 

woodmancy

Subscriber Member
Re: Pentax 110 lens on G1

I wouldn't go so far as say I "created" an adapter to be honest. I found a deal on E-Bay that included a 24mm and a 70mm lens with a non-functioning Pentax-110 body. I took the body apart and then stuck the lens mount onto a C-Mount adapter with black electrical tape.

If anyone needs images of what I'm talking about I'll be glad to whip out my trusty G9 and take shots of the "set-up" for y'all :D
I for one would love to see a picture - best shove it in the 110 thread that Vivek started

Thanks
Keith
 
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seb33

Guest
I've found on the WEB a c mount Vivitar 25mm 0.95.

Does anyone have ever heard about this lens ? I would like to buy it for my GH1.

Thank you
 

pellicle

New member
Hi

The sharpness demands on the optical printer lens were therefore extreme. What are the sharpness demands on the G1 picture taking lens?
surely that depends on you intended print size and willingness to accept softness. David Hamilton style images would no doubt be obtainable with a lens baby ... but I personally don't see much problem with old 35mm lenses from the 80's ... do you?
 
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seb33

Guest
Angenieux 25/1.4 is ok
Nikon cine nikkor 25/1.4 & Bausch & lomb 26/1.9 --> the front ring is a little too long.
So just small vignetting developed when wide open .
I've just bought a Nikon cine nikkor 25/1.4. Is it ok with GH1 ?
 

apicius9

New member
Well, since that thread is up anyway... I got a few few shots done today before and after dinner. Here are a few with the Zeika Nominar 25/0.95.







This lens keeps puzzling me. I have the suspicion that it needs work, infinity is not really sharp and, not surprisingly, it's also quite soft wide open (last picture, the others were slightly stopped down). Wide open it is difficult to focus in the dark, but that's more a general observation, I guess. I like the handling, it's a bit heavier than the other 0.95 c-mounts - I hope to get this serviced and then see again.

Stefan
 
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