The release of the ON-OFF-ON 645D seems to be approaching. According to the latest rumours it seems to be relatively speakingly affordable even at release and will most probably drop in price after a while. So, I suppose many of us are already drewling over this big time.

If one would start gathering Pentax 645 lenses in advance, would they most likely all work with a 645D like 35mm lenses work with new DSLRs? And assumably even auto-focus with FA 645 lenses? Which lenses would be recommended, ones that might still be found cheapish? I guess the lens prices have gone up since the spring announcement and latest rumours, right?

[surfotog]

They should all work, but keep in mind that the sensor will almost certainly be smaller than the 41.5 x 56mm image size produced by the film versiom, so the wide angle lenses won't be quite as wide. As to which lenses to get, that all depends on your shooting style. A few of the 645 lenses are hard to find and command premium prices, like the 35/3.5 FA and the 33-55 FA zoom.

[patrickhh]

They have announced a 55mm lens as standard lens, so the crop factor will probably be around 1.4

[Ron Boggs]

Just as what happened with the 35mm to digi crop...I'll recommend stocking up on 645 lenses OTHER THAN the wide angle. Buy the new wide angle that will surely be released with the camera...

In 35mm terms, all my lens kit directly swapped into the digital format with crop except for my wide stuff, so that's the only new lens I needed to convert from 35mm film to digicrop. Unless the 645 system offers a wide angle with completely jaw-dropping image quality that is several levels better than all the other lenses, I'd just skip the wide and choose a few longer lenses from the used market.

I don't have experience with the 645 system, so I can't tell you if you should own the wide angle stuff regardless of the new crop system lenses that will surely be coming out.

[tuco]

I haven't kept up with the 645D. What is the lure of this camera for the hefty price you'll have to pay?

[k100d]

They have announced a 55mm lens as standard lens, so the crop factor will probably be around 1.4

so the 645D will be almost the same as 35mm FF

[patrickhh]

so the 645D will be almost the same as 35mm FF

Yeah, but much more expensive, bigger, heavier and K mount incompatible.

[D W]

Most likely this sensor will be about 44X33 or 48X36. These are sizes of Kodak sensor presently on the market.
This makes the 645D sensor twice the size of 35mm frame of 24X36.

The announcement of a AFD55 make sense if you have been using 645. When the 645N and AF came out the 55 lens was one of the lens they did not come out with an upgraded AF version. By upgrading the 55mm lens to AFD (an existing design) would cut down on development time so they can concentrate the lens development resources on a wide angle lens in the 24-28 range which would be required by the new sensor.

When Pentax went Dslr with the APC-s sensor the first lens released was the DA14/2.8.

[Andi Lo]

If a teleconverter to correct registry distance can be made, it is perhaps possible to use the full frame K lenses on the 645D with minimal vignetting. Maybe an auto-crop mode like the Nikon full frame cameras? The TC better be good enough though....

[D W]

If a teleconverter to correct registry distance can be made, it is perhaps possible to use the full frame K lenses on the 645D with minimal vignetting. Maybe an auto-crop mode like the Nikon full frame cameras? The TC better be good enough though....

There is no need for Pentax to spend money on such a device.

The 645D is targeted at users of 645, 645N 645NII. There were estimates out of Asia that there are over one million of Pentax 645 variants bought world wide in it's history.

There are enough 645 A and FA lenses out there that Pentax need not to worry about a user base. All 67 lens can be used with Pentax OEM adapter which allows for auto stop down aperture.

[rparmar]

so the 645D will be almost the same as 35mm FF

Wrong conclusion based on a faulty premise. Please read my article Pentax 645 Digital On The Horizon which contains a chart comparing normal sizes for different sensors. The 645D will be significantly better than full-frame and a big jump from APS-C, though unfortunately not as large as proper 645.

Though maybe that should read "fortunately" since the price will be proportionally less as well.

[Cideway]

They should all work, but keep in mind that the sensor will almost certainly be smaller than the 41.5 x 56mm image size produced by the film versiom, so the wide angle lenses won't be quite as wide. As to which lenses to get, that all depends on your shooting style. A few of the 645 lenses are hard to find and command premium prices, like the 35/3.5 FA and the 33-55 FA zoom.

I have the 33-55 and it is a fantastic lens, and even if the 645D has a 1.3 crop my 33 will still be the equivalent of a 24 (ish), my favourite focal length

[Digitalis]

yup 2010 will be a BIG year for pentax, I have a few of my longer 645 and 67 lenses that are just itching to be used again...especially my pentax-M* 67 400mm on a 1.3 format MF Digital body, that would be quite nice for birding. I think I still have the 1.4 TC for that lens...starts rummaging through pelican cases...

[Pål Jensen]

I have the 33-55 and it is a fantastic lens, and even if the 645D has a 1.3 crop my 33 will still be the equivalent of a 24 (ish), my favourite focal length

Fantastic is taking it a bit far in my opinion. Edges are not sharp until F:11 (it has a curved focusing plane), although this will be less of a problem with a cropped sensor. It shows quite a bit of purple fringing (on film) and contrast is slightly lower than on the prime 45mm and the 45-85 zoom. I really think one would want to use the best prime lenses on the 645D!

[ARCASIA]

I think that all of the current A-645, FA-645 and 67 lenses will be able to be used on the 645D. I suspect that many of the discontinued FA-645 lenses are either in production now and being horded for release with the 645D, or will be back in production shortly.

The real beauty of the Pentax MF lines is that one can acquire MF capability with first rate optics for a reasonable price. The costly 645D changes the game entirely. Apart from MF professionals, I cannot see how many can justify the USD 8,000 price tag, especially given the beautiful pictures one can take with the film cameras at a mere fraction of the price, and given the fact that the sensor is not upgradable.

I believe that the release of the 645D will seriously affect the prices of used 645 and 67 lenses, the best of which are already difficult to come across.

For wide to medium tele lenses, I would recommend FA-645's – great glass and lovely AF. For long teles, the bargains lie in the 67 line. Here are a few for anyone trying to "stockpile" glass now:

1) FA-645 35/3.5 - Probably one of the best wide angles ever made for any system, but very hard to find now, in part thanks to all of the Canon people who prefer to shoot with it.

2) FA-645 75/2.8 - Just an inexpensive, incredibly useful FL lens that everybody ought to have in their bag. Interestingly, I have seen MTF results for this lens that makes it competitive with some the best 35mm lenses.

3) FA-645 150/2.8 - A wonderful portrait lens that competes with the best 35mm lenses - very sharp (for portraits) from f/4, great colour rendition, very nice out of focus rendition (even out of focus specular highlights with a little edge gradation, but a hint of double lines on branches, wires, etc.), and a 3-dimensional look in photos that rivals even the best that Leica has to offer.

4) FA-645 300/5.6 - This lens is so good optically, so light and convenient, and so inexpensive, that you will never pine for the FA-645 300/4.

5) 67 400/4 Takumar - The bargain in long lenses. Big and heavy (a good tripod is essential), but cheap in a world of expensive telephoto glass. Super sharp, good contrast and natural colour. No low dispersion glass, but it has a Cook apochromatic optical design that does a pretty good job controlling chromatic aberration, even by ED standards, particularly when stopped down a little (see Desertscape's accurate lens review for more info).

Regards, Alan