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07-11-2011, 07:10 AM   #1
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Ricoh 18.3/2.5 and 33/2.5 macro for K-mount? Do you want it?

Ricoh 18.3/2.5 and 33/2.5 macro are sharp from wide-open.
Compact (almost pancake) and very good optically.
Do you want such lenses for K-mount? How do you think - is it real?


Last edited by ogl; 07-11-2011 at 07:15 AM.
07-11-2011, 07:15 AM   #2
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Not personally, but I think there is a market for it.

Is there any rumor?
07-11-2011, 07:17 AM   #3
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QuoteOriginally posted by RonHendriks1966 Quote
Not personally, but I think there is a market for it.

Is there any rumor?
I think 18.6/2.5 MUST to be. I hope that 2012 year will be the year of new Pentax's lenses.
07-11-2011, 07:24 AM   #4
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The existing GXR lenses cannot be used/adapted to K-mount - their optical design won't allow enough mirror clearance.
"Is it real" - of course not.

07-11-2011, 08:01 AM   #5
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QuoteOriginally posted by Kunzite Quote
The existing GXR lenses cannot be used/adapted to K-mount - their optical design won't allow enough mirror clearance.
"Is it real" - of course not.
Explain it, please. Do you have optical formulas of Ricoh lenses?
8-group, 9-element configuration (aspherical lens: 1 element, two surfaces); low level of vignetting allows rich and genuine bokeh effects.
Nothing special.

Even FA43/1.9 was made for M39. Cosina and Zeiss lenses are made for all mounts.

Last edited by ogl; 07-11-2011 at 08:12 AM.
07-11-2011, 08:35 AM   #6
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Ogl, do you know what a retrofocus design is? I guess you don't. You also don't know what an aspherical lens is, btw.
Things are "slightly" more complicated than just counting the elements.
07-11-2011, 08:35 AM   #7
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QuoteOriginally posted by ogl Quote
Even FA43/1.9 was made for M39. Cosina and Zeiss lenses are made for all mounts.
Lenses made for SLR and DSLR have to leave a space for the mirror. Since the Ricoh lenses were designed to work for a mirrorless camera, they will not have that space.

You can adapt SLR lenses for mirrorless: that's why the FA43 could be made for the Leica. The Cosina and Zeiss lenses use different designs on SLR or on the Leica M mount (like Distagon on SLR and Biogon on Leica).
07-11-2011, 08:47 AM   #8
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Not much point to producing the second one. Only 2mm wider and a third of a stop faster than an existing lens, sounds like it's about the same size. Unless it's $100.

07-11-2011, 11:08 AM   #9
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Are we talking about GXR lenses? If so, it should be noted that the GXR system doesn't have interchangeable "lenses", but what you actually change is the whole lens+sensor assembly. So it does not make sense at all to talk about a K-mount adapter for GXR "lenses". And taking out the sensor part would mean to develop a completely new product, of course.
07-11-2011, 07:27 PM   #10
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QuoteOriginally posted by Kunzite Quote
Ogl, do you know what a retrofocus design is? I guess you don't. You also don't know what an aspherical lens is, btw.
Things are "slightly" more complicated than just counting the elements.
Dear Kunzite, I'm old man and know many various things....:ugh:
And if you want to feel yourself as intellectual, it's no problem.
Your criticism is accepted. You are right.

But...
1. Where is the source of your information that Ricoh makes retrofocus lenses?

2. Do you know that Canon 17-40 mm f/4 L is retrofocus zoom lens. For example.
And many wide-angle lenses are retrofocus lenses. Especially, for m4/3 system.

3. The single-lens reflex camera requires a space for the reflex mirror, imposing a limit on the use of wide-angle lenses of normal designs. The retrofocus lenses addressed this situation by shifting the focal plane further back than where it would normally be, thus making wider-angle lenses usable while retaining normal viewing and focusing.
Retrofocus design helps in creating wide-angle lenses. It's not obstacles.

4. If you consider that K-mount is a problem to create retrofocus lenses, explain me, please, why.
07-11-2011, 07:28 PM   #11
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QuoteOriginally posted by Paolo.Bosetti Quote
And taking out the sensor part would mean to develop a completely new product, of course.
Of course, based at existent optical design.
07-11-2011, 10:20 PM - 1 Like   #12
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QuoteOriginally posted by Kunzite Quote
Ogl, do you know what a retrofocus design is? I guess you don't. You also don't know what an aspherical lens is, btw.
Things are "slightly" more complicated than just counting the elements.
Care to enlighten us without being a prick? This is not common knowledge to all; and I do believe there is a polite and courteous way of informing others without resorting to rude remarks.
07-11-2011, 11:07 PM   #13
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I'm sorry, TAP - my message was directed entirely at ogl (for a reason) but of course, it wasn't nice of me - because you all could read it.
What is an aspheric lens, you're asking. I'm quite bad at explaining things, so I'll link at the wiki page (which has more information and explanatory images)
Aspheric lens - Wikipedia, the free encyclopedia
In short, it's a lens whose surface is not spherical; not the "aspherical lens: 1 element, two surfaces" ogl said it is.

Ogl:
1. I didn't said that; on the contrary, the issue is they aren't retrofocus enough (the 33mm I bet it's not retrofocus at all, I'm not very sure about the 18mm).
Both lenses are designed to be very close to the sensor; because it's possible (no mirror) and because a retrofocus design would only make things harder.
2. The Canon zoom, of course it is a retrofocus design. For m4/3 which lenses are retrofocus? I'd guess at least those under 20mm (which is the registration distance for this mount)
3. So, you can use wikipedia. Good.
4. did I ever said it's a problem? On the contrary: the K-mount wide angle lenses must and do have a retrofocus design, allowing for the required mirror clearance. Otherwise they wouldn't focus to infinity.
07-11-2011, 11:19 PM   #14
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QuoteOriginally posted by ogl Quote
Ricoh 18.3/2.5 and 33/2.5 macro are sharp from wide-open.
Compact (almost pancake) and very good optically.
Do you want such lenses for K-mount? How do you think - is it real?
Even if Ricoh made those standalone, retrofocus and for K-mount, I wouldn't want them. 18mm f/2.5? 15mm f/4 ltd is wider, and generally not used for any subject isolation anyway. 33 2.5? What's wrong with the DA 35 f/2.4 or DA 35 2.8ltd?

If your point is that they're pancakes, that's because they weren't made for k-mount.

So, no. Those focal lengths and apertures wouldn't interest me, I guess.
07-12-2011, 01:07 AM   #15
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I think a 18/2,5 would be a great addition to the Pentax line-up, while a 33 macro is basically a duplicate of the 35 macro limited.

That said, obviously the GXR lenses have not enough clearance to be adapted to K-reflex. But on a Pentax APS-C mirrorless they could work...
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