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04-25-2012, 11:29 AM   #76
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QuoteOriginally posted by deadwolfbones Quote
Elements look just about the same size to me (if the bodies were scaled properly).
Even if that is the case (I still think the element is a little larger), it is a lot larger than the front element on the DA 21 and DA 40. The scale matches the 40 in its most compact position.


Last edited by Blue; 04-25-2012 at 11:42 AM.
04-25-2012, 11:38 AM   #77
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to me this makes sense as a retro focus UWA like a 15 for the K-01 only. It could of course be a 70 of some design but retrofocus designs more typically have been Wide not long
04-25-2012, 11:42 AM   #78
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QuoteOriginally posted by eddie1960 Quote
to me this makes sense as a retro focus UWA like a 15 for the K-01 only. It could of course be a 70 of some design but retrofocus designs more typically have been Wide not long
Asahi Optical was into retro focus in the m42 era and the rear element still didn't protrude beyond the 45.46 mm registration distance to this extreme. I am not implying it is remotely close in focal length to the 70, just that it will seemingly have the largest front element of any of the 5 DA Ltd lenses to date. The focus distance marks are like the DA 40 ltd but then since it is a mocked up prototype, it could just be that focus ring they used from the parts bin.
04-25-2012, 11:49 AM   #79
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whatever it turns out o be it definitely looks to be K-01 only

04-25-2012, 11:55 AM   #80
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QuoteOriginally posted by eddie1960 Quote
whatever it turns out o be it definitely looks to be K-01 only
you could always try mirror lockup! lol
04-25-2012, 12:06 PM   #81
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QuoteOriginally posted by eddie1960 Quote
whatever it turns out o be it definitely looks to be K-01 only
Which doesn't make a lot of sense. That will create a lot smaller market for a LTD series lens. It still doesn't clearly explain the registration distance.
04-25-2012, 12:07 PM   #82
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QuoteOriginally posted by Blue Quote
Edit: If the registration distance is the same, why the protruding rear element?
Sorry, but it's the other way around: the lens protrudes into the mount because the registration distance is the same. The idea is to shorten the back element to sensor distance, while still using a K-mount. A perfect fit for a K-01-like camera (and yes, that's the only explanation that make sense).
04-25-2012, 12:12 PM   #83
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QuoteOriginally posted by eddie1960 Quote
to me this makes sense as a retro focus UWA like a 15 for the K-01 only. It could of course be a 70 of some design but retrofocus designs more typically have been Wide not long
QuoteOriginally posted by eddie1960 Quote
whatever it turns out o be it definitely looks to be K-01 only
Unless the K-01 contains the basic technology for future K-mount mirrorless bodies, including those with a viewfinder. If there is a complete MILC line with a 45.46mm register distance - even if it uses the K-r button layout and menu structure instead of the K-5 - the lens would be designatured for Mirrorless K-mount Cameras only.

Lens Lines:
Q
XS
DA
FA / D-FA
645

04-25-2012, 12:25 PM   #84
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QuoteOriginally posted by Kunzite Quote
Sorry, but it's the other way around: the lens protrudes into the mount because the registration distance is the same. The idea is to shorten the back element to sensor distance, while still using a K-mount. A perfect fit for a K-01-like camera (and yes, that's the only explanation that make sense).
This makes absolutely no sense. The k-mount is a 45.46mm registration distance. Now you are at the K-01 "like" camera. I supposed that that is a possibility. A new camera with a new registration distance. That is really what they need at this point.

K
Q
645D
K-bobbed :Hysterical:
Ricoh modular

:sarcasm:
04-25-2012, 12:29 PM   #85
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Blue, you keep saying registration distance while meaning the distance from the real element to the sensor. The registration distance is from the mount surface, it's unrelated to where the rear element is positioned. (Except of course that if the registration distance is larger than the distance to the rear element, it will protrude from the back of the lens.)

You also seem to think retrofocus means something fairly close to opposite what it actually means. (It's used to put the rear element further away from the image plane, and as a side effect makes the light rays more parallell, which is good for digital. All SLR wide angles that don't require mirror lockup are retrofocus.)
04-25-2012, 12:44 PM   #86
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the idea is no different than the LTM lenses like the Biogon 28 2.8 which protrudes into the body (as do the jupiter 12 Russian knockoffs). it's a very old lens idea actually dating back to 1935 and still amongst the best wide angle designs ever made (coatings etc can improve on the performance, but the design of the rear element getting closer to the film plane ended up in Medium format cameras and large format cameras (see the Hologon for instance)
registration distance is still the same even though the lens protrudes

It apparently was an effort to improve contrast - I can tell you my Jupiter 12 biogon knockoff is a really nice contrasty lens with great colour (the cool design effectively has a built in shade as well)
04-25-2012, 12:44 PM   #87
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QuoteOriginally posted by drougge Quote
Blue, you keep saying registration distance while meaning the distance from the real element to the sensor. The registration distance is from the mount surface, it's unrelated to where the rear element is positioned. (Except of course that if the registration distance is larger than the distance to the rear element, it will protrude from the back of the lens.)
yes, I know this. That is why it doesn't make a lot of sense to design a lens that protrudes so deeply into the body.

QuoteOriginally posted by drougge Quote
You also seem to think retrofocus means something fairly close to opposite what it actually means. (It's used to put the rear element further away from the image plane, and as a side effect makes the light rays more parallell, which is good for digital. All SLR wide angles that don't require mirror lockup are retrofocus.)
Nowhere have I said how a retro-focus lens operates. All I said is Pentax has designed them a long time, in fact one of the first for slr 135. Therefore, what you seem to think I think, is wrong.
04-25-2012, 12:49 PM - 1 Like   #88
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the retro focus was my error I believe - Biogons are non retro focal

jupiter 12 as you can see extends quite fare beyond the mount (no stinkin mirrors on an RF lol)

04-25-2012, 12:57 PM   #89
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Pentax has designed retrofocus lenses in the past the cleared the mirror at infinity. The first was the Auto-Tak 35/2.3 originally released in 1958. This is one of my favorite taks in fact. The rear element protrudes no where near that much at infinity focus.
04-25-2012, 01:03 PM   #90
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Blue, you should stop and try to understand things like "registration distance" and "retrofocus" instead of arguing. Currently, you don't.

A K-01 like camera is a mirrorless camera with a K-mount, i.e. the same registration distance. It's easy to understand such a lens, if you know the basics:
a. the K-mount is kept for compatibility reasons (all K-mount lenses can be used directly). Which means the same registration distance (doh!).
b. the space where the mirror was is now "free", and such a lens can extend into it (a good thing, for wide angle lenses). OTOH, if you'll try to put it on a DSLR the protrusion will hit the mirror (or at least, block its movement) - thus, is a K-01-only lens.

The alternative would be a new mount, with a smaller registration distance (K-mount being usable with an adapter). Sony did it with the NEX and, guess what - the registration distance is so small there is no need and no space for lenses to protrude into the mount.

Even your insistence that old retrofocus K-mount lenses does not protrude into the mount shows your lack of understanding. Of course they don't, since they were specifically designed to leave enough room for the moving SLR mirror (mirror clearance). That's what the retrofocus design does.
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