M lens and earlier, what settings ?


Transit

Link Posted 28/04/2012 - 03:28
Hi Folks

I was having a wee go with my M85/2 this morning,
I usually shoot in Av if wanting wide open
and M with green button if I want stopped down.
Was wondering how auto iso works with non A lens. It seems to function in various modes.
I wonder if I'm making the most of the K-5 with this glass

what settings do you use with M, K lenses ?
thanks for any thoughts

Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

sterretje

Link Posted 28/04/2012 - 04:17
M and green button; I hardly ever use auto ISO.

And you make the most of the K5 if you're happy with the results It does not matter how they are achieved
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)

Transit

Link Posted 28/04/2012 - 23:32
sterretje wrote:
...
And you make the most of the K5 if you're happy with the results It does not matter how they are achieved

Thanks
I see what you mean but not my logic. I get as much enjoyment out of the use as from the results. If there are better ways to use the camera in this specific way, I'm keen to know about it
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

sterretje

Link Posted 29/04/2012 - 06:26
Transit wrote:

Was wondering how auto iso works with non A lens.

Transit wrote:

I get as much enjoyment out of the use as from the results.

In which case it sounds like you like to experiment. Just try it out I often do so when I reply to questions asked on forums as it helps me to understand / learn the camera. Unfortunately my M and M42 lenses are packed away so it's not a quick exercise to play with.
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)
Last Edited by sterretje on 29/04/2012 - 06:27

JAK

Link Posted 29/04/2012 - 11:49
Transit wrote:
I was having a wee go with my M85/2 this morning, I usually shoot in Av if wanting wide open
and M with green button if I want stopped down.

Yes, it's supposed to work like that, but regarding your query

Transit wrote:
Was wondering how auto iso works with non A lens.

I can't see that it can as the camera needs to know both shutter speed and f stop to work that out. While the camera will be aware of the shutter speed, non A lenses don't pass any information to the camera so it has no means of calculating an auto ISO. All you can use is M with the green button or Av at full aperture as you said.

John
John K
Last Edited by JAK on 29/04/2012 - 11:52

Helpful

helios

Link Posted 30/04/2012 - 01:15
This is an interesting question. I have just tried a little experiment.

I do not have a non A lens handy but using an A lens set to a fixed aperture (i.e. not at the A setting) you are quite right. Using AV at full aperture auto ISO works ok. With a set aperture auto iso does not work but setting a fixed ISO and using the green button does work well.

Your best bet then is to use fully manual settings of both aperture and ISO and meter using the green button.

It is really quite impressive how well the current K-5 works with older lenses.
Archie

ChrisA

Link Posted 30/04/2012 - 12:54
helios wrote:
It is really quite impressive how well the current K-5 works with older lenses.

Stop-down metering certainly works a lot better with the K-5 than it did with the K10D.
.
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)
.

prsjnb

Link Posted 30/04/2012 - 15:27
ChrisA wrote:
helios wrote:
It is really quite impressive how well the current K-5 works with older lenses.

Stop-down metering certainly works a lot better with the K-5 than it did with the K10D.

[quote:3496ace15f="ChrisA"]


Absolutely When compared with the K10 or K20, exposure in A-mode with the K5 and K or M lenses is considerably more accurate and predictable, allowing one to dispense with stop-down metering for the vast majority of shots. This has been my experience using lenses ranging in focal length from 50 - 400mm (Pentax and third-party).

Why the K5 should be so delightfully different in this respect I cannot say, but would be interested to hear from anyone who knows or thinks they might know.

Jon

ChrisA

Link Posted 30/04/2012 - 17:45
prsjnb wrote:
When compared with the K10 or K20, exposure in A-mode with the K5 and K or M lenses is considerably more accurate and predictable, allowing one to dispense with stop-down metering for the vast majority of shots.

Is it possible a lot of these shots were taken with the lens wide open?

If not, I don't see how the exposure would be any more accurate without stop-down metering.

The whole point is that the camera cannot tell what the lens aperture is set to, and the lens does not stop down until the picture is taken.

So if you don't stop it down with the green button, the exposure is determined with the lens wide open - the camera doesn't get to meter with the lens at its set aperture.

Stop-down metering was rubbish with the K10D and K20D, and it's been improved a lot with the K-5 (maybe the K-7 was also Ok in this regard, I don't know).

But the mount itself has not changed. So the camera still has no idea what the aperture ring is set to. Ever.
.
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)
.
Last Edited by ChrisA on 30/04/2012 - 17:46

prsjnb

Link Posted 30/04/2012 - 18:20
ChrisA wrote:

Is it possible a lot of these shots were taken with the lens wide open?

If not, I don't see how the exposure would be any more accurate without stop-down metering.

That would be my understanding too, Chris. In practice, however, I have found repeatedly that I can shoot in A-mode over a range of 3 stops (1.8 - 5.6 on my K 55mm, for example) and still obtain well exposed shots (even when shooting JPEGs): a practice I wouldn't dream of indulging in with either the K20D or the Samsung GX-10, which I presume behaves similarly to the K10.

Is it possible that this different, and completely counter-intuitive, behavior of the K5 when compared with the earlier bodies could be function of its sensor: in particular its enhanced dynamic range and hence greater exposure latitude?

Just to be clear, it was not my intention to suggest that one could dispense totally with stop-down metering when using the K5 with manual lenses. Rather, I was seeking to communicate that this 'fortuitous aberration' makes the use of manual lenses with the K5 a little less demanding and somewhat quicker.

Best wishes,

Jon

ChrisA

Link Posted 30/04/2012 - 18:28
prsjnb wrote:
Is it possible that this different, and completely counter-intuitive, behavior of the K5 when compared with the earlier bodies could be function of its sensor: in particular its enhanced dynamic range and hence greater exposure latitude?

Yes, I'd imagine it could only be the better sensor in that case. I'm surprised it gives you as much as three stops (a factor of 8 in terms of actual quantity of light )

Do you have shadow/highlight correction on?
.
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)
.

Algernon

Link Posted 30/04/2012 - 19:19
Most manual lenses overexpose wide open so it's hardly surprising
that you can stop down to f/4 - f/5.6 and still be within
an acceptable limit

You need to go back to basics

I've never thought of auto ISO, but I expect that might
work with an 'M' lens that has had the aperture lever cut off
and possibly with a preset-lens as well.
Half Man... Half Pentax ... Half Cucumber

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

Algi

JAK

Link Posted 30/04/2012 - 23:22
I've just tried to see what happens by setting an A lens to a manually set aperture in TAv mode on my K-5 which is the one that sets auto ISO value. The camera shows Av mode, not TAv. As an M lens would be no different, the K-5 doesn't actually let you use it in that mode!

As said many times above, for TAv to work the camera has to know both the shutter speed and f stop that has been set. If an A lens passed its setting through to the camera body in non 'A' mode then in theory it would work, but it doesn't and was never designed to work that way. Auto ISO will not work with non A lenses.

As regards using the K-5 like an ME, that is setting an aperture on an 'M' lens at anything other than wide open and exposing the picture in Av mode without using the green button first, then it is pure luck if the resultant image is useable. I'd not recommend it for the shot of a lifetime! M lenses need to be used in M mode (or in Av if kept wide open) and the exposure set with the green button.

Bojidar Dimitrov's article on the crippled KAF mount is here: link

John
John K

Transit

Link Posted 01/05/2012 - 11:45
Algernon wrote:


I've never thought of auto ISO, but I expect that might
work with an 'M' lens that has had the aperture lever cut off
and possibly with a preset-lens as well.

Presets are easy to use in Av, love the smooth stop down
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River

Transit

Link Posted 01/05/2012 - 11:50
JAK wrote:
.... Auto ISO will not work with non A lenses.

John

I think this is incorrect ? I have auto iso working in TAv, Av and Tv with my M85/2. The lens stays wide open of course.
Pete
K-1 K-01 Q-7
some len

Close to the Edge
Down by the River
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