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04-29-2010, 06:20 AM   #1
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Pentax 645D and LS lenses

In the Pentax Lens Reviews Database description of the Pentax 645 75mm LS says: "and the lens is not suited for the 645D" Why? you can't fire the leaf shutter?

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04-29-2010, 06:58 AM   #2
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QuoteQuote:
It has no A setting so Program and Tv exposure modes are not supported, and the lens is not suited for the 645D.
I can also only guess - perhaps the author can´t imagine a digital photography without automatics ?
04-29-2010, 07:00 AM   #3
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I just read that for myself...and it has me scratching my head too, I thought pentax was satisfied with their telephoto lenses for the 645 - they were just adding modernised wide angle lenses to refresh some of the older designs which didn't perform well on the digital sensor.

"It has no A setting so Program and Tv exposure modes are not supported, and the lens is not suited for the 645D."

- but most studio photographers like myself don't give a crap about that!...most photographers who work in the studio/ on location typically shoot manually...and are the target audience for a leaf shutter lens in the first place.
04-29-2010, 07:19 AM   #4
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I just looked at description of the 135LS lens
QuoteQuote:
SMC Pentax 645 LS 135mm F4
....
It has no A setting so Program and Tv exposure modes are not supported and the lens is not suited for the 645D.
Hmm I personaly would support the view of digitalis.

04-29-2010, 05:40 PM   #5
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While there is a problem with user reviews, especially when there are not many of them, or even only one—they can be too subjective or manipulated by someone who wants to sell—this is the description in the database.This is surely not an established opinion, but would appear to be a user preference for A-settings. If so, it should be corrected.

Last edited by Smolk; 05-05-2010 at 05:37 PM.
05-06-2010, 12:09 PM   #6
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QuoteOriginally posted by Ramón Quote
In the Pentax Lens Reviews Database description of the Pentax 645 75mm LS says: "and the lens is not suited for the 645D" Why? you can't fire the leaf shutter?

Ramón
PENTAX's press release on the 645D states that the camera is compatible with

PENTAX 645AF2, 645AF, and 645A mount lenses.

Until we see some hands-on reviews we won't know if there might be a solution for LS lenses (like the green button metering on the K20D etc.).

Last edited by Ole; 05-06-2010 at 10:33 PM.
05-06-2010, 02:46 PM   #7
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QuoteOriginally posted by Ole Quote
PENTAX's press release on the 645D states that the camera is compatible with

PENTAX 645AF2, 645AF, and 645A mount lenses.
But isn't the LS lens technically compatible with the 645A mount even though it is not an A lens? (Not meant to be rhetorical)
05-06-2010, 05:03 PM   #8
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QuoteOriginally posted by Smolk Quote
But isn't the LS lens technically compatible with the 645A mount even though it is not an A lens? (Not meant to be rhetorical)

That's a bit of a dumb question..If it isn't and A series lens then it certainly isn't going to behave like one. As stated in the 645D specifications the camera will be compatible with every 645 lens pentax has produced. It may be possible to convert one to the A-mount but if you take a look at those who have tried to convert 35mm M series lenses to A series it isn't as easy as just adding as adding pin or two on the mount of the lens... it doesn't work, simply because aperture control mechanism is slightly different in A series lenses.

05-06-2010, 07:21 PM   #9
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Not too quick. The confusion about LS on 645D which made you scratch your head too resulted from

1) the comment in the lens review database which states that LS lenses "are not suited for the 645D" (whatever suited means here)

2) the comment about the compatible mounts (AF2, AF, A) in the press release which Ole quoted, and which made him say that "we won't know" until we have a hands-on review of LS on 645D.

But I think that the mount does not imply that the LS lenses won't work. The LS was designed to work with the A mount after all, even though its aperture cannot be controlled by the camera. That leaves the meaning of "suited" in 1).

There is, however, a difference between A and FA lenses which I haven't seen any comment on (hope I did not miss it), and it has nothing to do with autofocus. According to the same press release, CA correction will be possible for FA lenses but apparently not for the A ones.
05-07-2010, 12:48 AM   #10
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QuoteOriginally posted by Smolk Quote
According to the same press release, CA correction will be possible for FA lenses but apparently not for the A ones.
IMHO A-lenses are not "intelligent" for the 645D (no chip inside)- so the processor isn´t able to calculate a CA correction.
It also shows to me that Pentax hasn´t included a lens database (like Nikon or Leica) for herritage lenses in the P645D, where you can register herritage lenses manually.
05-08-2010, 05:25 PM   #11
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QuoteOriginally posted by veraikon Quote
It also shows to me that Pentax hasn´t included a lens database for herritage lenses in the P645D
Wouldn't that be something a firmware update could deal with? (Here's hoping...)

Last edited by Smolk; 05-08-2010 at 05:31 PM.
05-08-2010, 08:57 PM   #12
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When you think about the whole mechanism of the LS lens, there is no reason why it would not work.

The aperture stop down lever on all P645 A mount lenses stop down the aperture working aperture, closes shutter, focalplane shutter opens to 1/8 sec or longer, shutter fires and close. the P645D stops down the aperture the same way to work with A and FA lenses.

The lens reviewer is doing everyone a disservice by commenting that the LS lens are not compatible without firsthand testing or verification of the source
05-09-2010, 12:54 PM   #13
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Pentax could yet have a surprise or two up their sleeves. Have they stated categorically that the 645D is shipping without an electronic shutter as well as the mechanical focal-plane one? Being that it's got a CCD sensor, there would seem to be that potential. With such an electronic shutter, all P645 lenses would function with as LS ones to X-sync with flash at every speed (but without having to manually cock them).

(Who knows whether it might simply be a firmware upgrade from what they've demo'd?)
05-09-2010, 06:31 PM   #14
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the electronic shutter approach is not without it's shortcomings the nikon D70 was able to do this( at 1/500th) but there was a problem with artefacts appearing in the images afterward.
05-09-2010, 10:27 PM   #15
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OTOH, the D70 (and D50 perhaps?) quickly became a favorite among hummingbird photographers for this very feature.
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