DSLR zoom lenses on GXR M mount

[cerbay]

Hello,
Has anyone tried DSLR zoom lenses on GXR M mount module?
Can it be A cheap alternative to A16? (I know that there is no auto focus)
For example Nikon or Canon or Pentax 18-55mm kit lenses?
How is the ergonomy?
Is it possible to change aperture manually?
And the photo quality...?
Thanks in advance

[marathoni]

Hi cerbay,
everything is possible...
Have a look here: http://dc.watch.impress.co.jp/docs/revi ... 07092.html

[odklizec]

Hi cerbay,

I'm afraid, most of today's DSLR lenses are electronic driven, which means focus and in many cases even the aperture operation requires source of power. That said, the only lenses you can uses with the M mount are pure mechanic (film-age) lenses + those lenses made directly for the M mount. And of course, you need to acquire an appropriated "xxx-to-M" adapter. However, as far as I know, most of old zoom lenses are less than useful with digital cameras. Chromatic aberration and corner softness are the typical problems. Plus most of the old zoom lenses hardly start at anything lower than 28mm. And an old 28mm lens, if attached to the M mount, is an equivalent of 42mm lens.

In other words, you would have to find 16-57mm lens to get a similar focal length like from the A16 24-85mm. I really doubt there is an old zoom lens starting at 16mm?

[ayewing]

Hi cerbay,

Pavel has given a very clear account of the problems in using DSLRs on the GXR M Mount. I quite like a challenge and have managed to use an old Pentax zoom. As Pavel said none of the modern electronically controlled zooms will work but as long as the zoom has an aperture ring which allows you to set the aperture manually it can be used. I have an old SMC Pentax-A f3.5-4.5 35-70mm zoom lens which I think was the sort of kit lens that might have come with a film SLR. Using a fairly cheap PK-LM adapter the setup looks like this:-

dev-1068-4.jpg (232.72 KiB) Viewed 1007 times

---

EXIF-Data

Image taken on: Wed May 23, 2012 3:58 pm

Focus length: 53 mm

Shutter speed: 1/100 Sec

F-number: F/5.6

ISO speed rating: 200

Whitebalance: Manual

Flash: Flash fired, compulsory flash mode

Camera-model: PENTAX K-5

Exposure program: Aperture priority

Exposure bias: 0 EV

Metering mode: Spot

and this is an image taken using it

dev-0011392-2.jpg (376.97 KiB) Viewed 1012 times

---

EXIF-Data

Image taken on: Wed May 23, 2012 3:42 pm

Shutter speed: 1/180 Sec

F-number: F/1

ISO speed rating: 400

Whitebalance: Auto

Flash: Flash fired, compulsory flash mode

Camera-model: GXR MOUNT A12

Exposure program: Aperture priority

Exposure bias: 0 EV

Metering mode: Center-weighted average

So it is quite possible provided you do not mind setting the aperture and focusing manually. I do not think that I will be doing it very often as I recently got an A16 zoom camera unit which is much easier to use apart from zooming which is much easier on the old manual zoom.

[Tom Caldwell]

I have a Pentax-K 24-35mm f3.5 that I bought new in the early 1980's. Neat, fairly compact zoom that works well. Cannot understand the seeming aversion to manual ex-slr lenses in zoom configurations. They are easy to mount and use but Pavel's comment on effective focal length range is very pertinent. Fast old wide zooms also tend to heavy - just think the more sought after Canon red-ring lens of identical capabilities to the Pentax I have noted - much larger and heavier lens but possibly not necessarily performing better because of it.

The later designed (late 1980's?) Canon FD 35-105mm f3.5-4.5 is of composite construction and much lighter, handles well, and cost me just $60 for a pristine example. Call this a "kit lens" if you must, it works well enough in practice. Generally the price of old zooms is not the problem, nor difficulty in use.

Just depends on what is personally needed and acceptable really. I think zooms are bought for convenience and as such motor driven zoom, auto focus and aperture settiing are part of that convenience and therefore are appealing to another market than the one where users get excited by the rigours of using manual prime lenses. Despite having a few manual zoom lenses for interest I still prefer using prime lenses.


Tom

[cerbay]

Hello,
Thanks for all comments.
What made me post this topic is the below Nikon adapter.
http://www.ebay.co.uk/itm/150796336215? ... 1423.l2649
As far as I understand, I can use the Nikon DX lenses that are designed for APSC size sensors with the help of that adapter (it is possible to change aperture manually)
For example a non VR 18-55mm or a 18-70mm lens might be interesting. (especially for the wide angle side, as it isn't easy to find wide angle lenses for the GXR M mount)
I will not be surprised if it performs better than Nikon D90 or other 12 MP DSLRs for sharpness wise

[Tom Caldwell]

Hello,
Thanks for all comments.
What made me post this topic is the below Nikon adapter.
http://www.ebay.co.uk/itm/150796336215? ... 1423.l2649
As far as I understand, I can use the Nikon DX lenses that are designed for APSC size sensors with the help of that adapter (it is possible to change aperture manually)
For example a non VR 18-55mm or a 18-70mm lens might be interesting. (especially for the wide angle side, as it isn't easy to find wide angle lenses for the GXR M mount)
I will not be surprised if it performs better than Nikon D90 or other 12 MP DSLRs for sharpness wise

There are some adapters for lenses without aperture rings that can use a slide to move the aperture mechanism. Novoflex make one for the PK mount which is mechanically connected. Theses slides or levers have no stops and the aperture is simply judged. As there is little movement given the aperture cannot be finely set but it does work and is better than nothing.

However lenses with electronic aperture control cannot be worked this way - Canon EF is definitely so and I presume that modern Nikon mounts and others are similarly not adjustable - these lenses only work at wide open all the time.

The words that accompany this adapter seem to indicate that it will not help control the aperture on a Nikon lens: "Using this adapter, although the lens will fit physically, automatic diaphragm (AE metering), or any other functions are not retained using this adapter. In this case the user will need to meter in "stop-down mode" since the lens does not have the ability to have its aperture controlled by the camera body."

Tom

[AlbertTRAL]

I will not be surprised if it performs better than Nikon D90 or other 12 MP DSLRs for sharpness wise

You may bet! The sensor in the A12M is the D90 sensor but without AA filter. The outcome is that you have a resolving power that exceeds that of the last gen sony sensor of 16M included in the NEX5-N or D7000 at the cost of possible moiré (changing slightly your POV or stopping down seeking some slight diffraction can avoid the issue).
Check:
http://ricoh-gr-diary.blogspot.com.es/2 ... ex-5n.html

Speaking about nikon new zoom lenses, as you may know already, if you want to have complete control on the exact aperture, this means having the aperture ring, you must look for lenses WITHOUT G...(G...Gelded). If not, you must use one of those adapters pointed by Tom (Novoflex has). I am not aware of DX lenses without G...

[Tom Caldwell]

Interesting that in English a racehorse that is no longer a stallion is "gelded" and becomes a gelding. To I guess it makes sense that a lens that loses it's aperture ring has also been gelded. (grin)

Tom