Will the Pentax K-mount ever be "de-crippled"?


froeschle

Link Posted 27/09/2012 - 15:01
Help to restore an aperture ring coupler in future Pentax DSLRs:
http://www.pentaxforums.com/forums/pentax-dslr-discussion/200075-pentax-ricoh-de...

johnriley

Link Posted 27/09/2012 - 15:38
This has been the state of things since the film SLR era and the petition makes the assumption that doing this would be low cost and easy. It might not be, otherwise why let it be dropped in the first place?

Interesting thought though.
Best regards, John

froeschle

Link Posted 27/09/2012 - 15:56
Quote:
why let it be dropped in the first place?

http://kmp.bdimitrov.de/technology/K-mount/crippled_AF.html
Quote:
The only reason for the existence of this mount variation is cost cutting. This was achieved by leaving out the stop-down coupler of the body mount and the aperture ring of the lens mount. With this move Pentax sacrificed one of its strongest advantages, the unrivaled K-mount compatibility.

johnriley

Link Posted 27/09/2012 - 16:08
Thanks, that's what I thought. However, seeing lenses from A series onwards can be quite happily used with no problem, and that stretches back some 40+ years, is it so unreasonable?

Maybe it is unreasonable and maybe it would be useful to have a full version of the mount again. What do people think?
Best regards, John

froeschle

Link Posted 27/09/2012 - 16:29
Quote:
However, seeing lenses from A series onwards can be quite happily used with no problem, and that stretches back some 40+ years, is it so unreasonable?

You could use the aperture ring with all M/K/A/F/(D)FA lenses again without issues. So, there would be advantages even for newer lenses. One could e.g. choose aperture at the lens and use the two wheels of the body to set e.g. time and ISO. Flash and metering problems of K/M lenses would be cured - more or less effectively making them A lenses. Nikon supports such a feature already in the D7000. Even Canon has just reintroduced aperture rings for HDSLR video.

Don

Link Posted 27/09/2012 - 17:31
I would hope that in this day of electronics that a simple hybrid ring could be made... drop the mechanical linkages, but leave the aperture ring as an electronic control for aperture... bring out a lens that has the classic look and feel of an aperture ring.
of course that would only work on digital bodies.....
but having had the k10 slip off the right aperture (by bumping the edials) by accident durin event shoots with studio lights, there is something reasuring about the old aperture ring...

I think Pentax needs to develop "cinema" lenses, for the k-01 and come out with a k-01 with 4k video and live, raw hdmi out...
Fired many shots. Didn't kill anything.
Last Edited by Don on 27/09/2012 - 17:34

punkrockemo

Link Posted 27/09/2012 - 20:08
In the Pentax itnerview with Pentax Forum they said they would include apeture coupler if there was demand for it.

Quote:
Q Are there any plans of “de-crippling” the Pentax K mount so that lenses with aperture rings can be used outside of M mode, without having to stop down? In other words, will the aperture flange ever find its way onto a Pentax DSLR?

A It used to be that aperture was adjusted by aperture rings, but technologies have been development, and we think that aperture rings now have less importance to the user.

However, we understand also the importance of adjusting the aperture by the aperture ring. If the number of “voices” about this increases, we will plan to develop such a product. for me it all depends on how much it adds to the cost of the camera as i only have one lens that would benefit from it and the green button provides a work around for not having it.

For me it depends on how much it adds to the cost of the camera if i want it or not, the green buttton act as a work around and i only have one lens that would benefit.

Personally i think using the dial is more conveniant.
Last Edited by punkrockemo on 27/09/2012 - 20:08

gartmore

Link Posted 28/09/2012 - 06:58
I would definitely prefer an aperture ring on the lens, mainly because I find it easier (old habitué die hard) and other cameras I use have it.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

ChrisA

Link Posted 28/09/2012 - 09:13
Uncrippling the mount just doesn't seem to be enough of a priority, given all the other things they could be working on. I got rid of all my M lenses ages ago, and I much prefer the dual e-dial method of changing settings.

Stop-down metering is good enough now, on the K-5, and hopefully on its successors, so in the event I needed to use a pre-A lens, I think the metering issue has largely gone away.

So much as I'd like the Pentax cameras to be more compatible with old lenses in principle, in reality I can't get too excited about it.
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.

MattMatic

Link Posted 28/09/2012 - 09:16
Quote:
So much as I'd like the Pentax cameras to be more compatible with old lenses in principle, in reality I can't get too excited about it.

Ditto.

It would have been nice years ago when I still had M lenses.
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

Jonathan-Mac

Link Posted 28/09/2012 - 09:31
I would love a de-crippled K-mount and would be prepared to pay extra for it.
Pentax hybrid user - Digital K3 & K200D, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X digital
Fan of DA limited and old manual lenses

InFESTation

Link Posted 28/09/2012 - 09:38
That would be great, I do miss using the aperture ring, much rather have that than the e-dial
Pint o' rough & a game o' darts anyone

Algernon

Link Posted 28/09/2012 - 09:39
The Green Button is great because it works the same as the Spotmatic
did with stop down metering. It's like having a digital Spotmatic
with KM mount lenses.

Later open aperture metering was always inaccurate and still is,
because of vignetting of the lens wide open and digital not
seeing beyond about f/1.8. Olympus had it right by metering
off the actual film.

I think it was Lowell Goudge from the thread you refer to who
posted graphs of exposure errors at various apertures.

You can see visually from the following grey card exposures
that f/5.6 is more reliable than f/2.8 (wide open in this case)
for taking exposures. f/22 becomes unreliable due to diffraction.
f/1.4 or f/1.7 even worse and some lenses vignette really bad
wide open.

I remember some lenses on a Z-1 being up to 2 stops out.




It's time Pentax users allowed Pentax to run their business
how they want and not how some people think they should
run it.... leave the management to the management

-
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Last Edited by Algernon on 28/09/2012 - 09:40

froeschle

Link Posted 28/09/2012 - 12:36
Test procedure: An image of a white area was taken with an A-lens and a K-5 at several f-stops (x-axis), the grey scale value of the image then was determined with Photoshop (y-axis).
Blue curve: Lens set to A, aperture value set in camera (which would be similar to the usage of an uncrippled mount).
Red curve: Aperture value set at lens, usage of green button (note the deviation from the blue curve and/or a constant value: the fluctuations correspond to about two f-stops -> predictiveness?)

http://forum.digitalfotonetz.de/viewtopic.php?t=82962

-> Metering at open aperture plus an additional correction corresponding to the real f-stop (i.e. what an aperture coupler would automatically do) is more accurate than using the green button.


Already over 60 supporters of the petition .

Smeggypants

Link Posted 28/09/2012 - 13:45
ChrisA wrote:
Uncrippling the mount just doesn't seem to be enough of a priority, given all the other things they could be working on. I got rid of all my M lenses ages ago, and I much prefer the dual e-dial method of changing settings.

Stop-down metering is good enough now, on the K-5, and hopefully on its successors, so in the event I needed to use a pre-A lens, I think the metering issue has largely gone away.

So much as I'd like the Pentax cameras to be more compatible with old lenses in principle, in reality I can't get too excited about it.

What Chris said ^^^


.
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
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