smc PENTAX-D FA645 25mmF4AL[IF] SDM AW

smc PENTAX-D FA645 25mm (Photo by Pentax)

Pentax has announced that a new super wide lens will arrive in April for the Pentax 645D system. It looks like it will be an amazing piece of equipment. At 25mm it will be the equivalent of a 19.5mm lens on a FF 35mm camera. If mounted on a film 645 camera (or a future full frame 645D) it will be the equivalent of 15.5mm. Similar to the new 55mm it has excellent optics enclosed in a weatherproof body. An interesting thing to note is the built in filter holder behind the large curved front lens. The dial on the left allows you to rotate a circular polarizer while the filter is sealed away inside the lens. This is a great feature, and is something I really like about my huge 67 400mm lens. A few things that may rise a few eyebrows…

At 1070 grams this is going to add a fair bit of weight to your camera bag.

At around 4000 dollars (￥361,782 at Amazon.co.jp) this is a serious amount of money.

It is very pleasing to see that Pentax is continuing to develop new lenses for the 645D system. One of the initial worries about the 645D camera was the lack of wide angle lenses, making the system quite limited when used alone. Now with the arrival of the 25mm, there is a least the possibility of going wide, I just need to sell a kidney to do so 🙂

6 Comments

Janne says
- February 26, 2011
Does it cover full frame, though? I suspect not, but if it does, it’s probably one of the widest rectilinear lenses ever to have been made for medium-format cameras.

travel67 says
- February 27, 2011
Yes it covers the full frame. And yes I think it is the widest lens available for medium format. Unfortunately you can’t make the most of it while shooting with the current 645D, but what a piece of engineering.

Shaun M says
- February 27, 2011
Thanks for posting the details on this lens, Chris. I did not know how the weather sealing on the CP filter holder worked until now.

I’ll be very interested to see how sharp this lens is, and how the autofocus works with the 645D.

Chris Stone says
- February 28, 2011
My reading of the Pentax material on this lens was that when fitted to a film 645 camera it is a 25mm lens with the field of view of a 25mm lens. (Previously the widest Pentax lens was a 35mm.) So on a 645 film camera this provides new wide angle possibilities.

On a 645D it would have a reduced field of view making it equivalent to a 35mm lens on a film 645, while the old 35mm lens would now have the field of view of a 48mm lens. The new 25mm would then restore the wide angle field of view that the 35mm lens used to give 645 film cameras.

The fact that it seems to cover full frame 645 could mean that Pentax are future proofing their new lenses for when a full frame 645D is released.

Regards

Chris Stone

travel67 says
- February 28, 2011
Hi Chris S.,

I agree that Pentax is looking to the future by making it full frame, and at the same time making it backwards compatible with the 645 film camera.

The 19.5mm and 15.5mm equivalents for the lens were taken from the Pentax website (as was the image). I’ll try and find the link again to post on here.

Chris W.

Janne says
- February 28, 2011
I suspect the backwards compatibility is a major reason. They have a huge installed base of film cameras, and it’s probably worth it trying to sell this lens to them as well. Especially if you can make the argument that you can keep your film body as backup even after you transition to digital.

Chris S.: a 25mm lens is always 25mm of course. On a 6×4.5 format film camera, 25mm has the same angle of view as a 15.5mm lens on 35mm. On the 645D it has the same angle of view as an 20mm lens on 35mm. This is approximate, of course; the image ratio is different between the formats and besides, the true focal length is never really exactly the stated one anyway.