K-1 Automatically stops down my Pentax-a 50mm 1.4 in live view.

D1N0 · 06-13-2019, 11:01 AM

Originally posted by stevebrot

This trick works on my K-3. Do you know if all models follow this behavior for magnification?

Steve

My K-5 does so as well (I almost never used live view in the K-5)

---------- Post added 13-06-19 at 20:06 ----------

Originally posted by shardulm

"I don't know what I am doing but somehow its K-1s fault..."

I do know what I am doing, I don't know what the K-1 is doing stopping down for me to an unspecified aperture

pschlute · 06-13-2019, 11:28 AM

Originally posted by D1N0

My K-5 does so as well (I almost never used live view in the K-5)

---------- Post added 13-06-19 at 20:06 ----------

I do know what I am doing, I don't know what the K-1 is doing stopping down for me to an unspecified aperture

Do you want to see an image on the LCD screen that you can make sense of or not ?

D1N0 · 06-13-2019, 11:32 AM

Originally posted by pschlute

Do you want to see an image on the LCD screen that you can make sense of or not ?

I can make sense of images on the lcd screen with my m42 and m lenses that I can make sense of. I must have super powers.

pschlute · 06-13-2019, 05:00 PM

Originally posted by D1N0

I can make sense of images on the lcd screen with my m42 and m lenses that I can make sense of. I must have super powers.

With those lenses the camera will change the brightness of the screen so that you have an image to focus on. Why it does not simply do that with a modern lens I know not.

Try this also. With a modern lens in LV note how it behaves differently between say Av and M. In M it does not stop down the lens

stevebrot · 06-13-2019, 05:59 PM - **3 Likes**

Originally posted by pschlute

With a modern lens in LV note how it behaves differently between say Av and M. In M it does not stop down the lens

Not wanting to be contrary, but I just spent several hours doing M mode live view work with a KAF2 lens on my K-3 and can confidently report that the lens does do the protective stopdown in bright light and opens up again when things are dimmer. It will also dim the display in tune with the exposure simulation when EC is applied and will balance that against the aperture magic to give a consistent display brightness. The camera will also normalize screen brightness for very bright and very dim subjects, but defers to exposure simulation when that is invoked.

When using the aperture ring on a K-mount lens, the camera never does the protective stopdown but will apply exposure simulation based on EC and then only in Av mode. The screen never darkens with aperture change unless stopped down. It will also normalize screen brightness. M42 is similar except that with it exposure simulation works in both Av and M modes with EC.

Strangely, this is not particularly confusing in actual use.

Steve

D1N0 · 06-08-2022, 03:47 AM

I've noticed this can cause problems similar to sticky aperture. The camera can't open up the aperture fast enough for a wide open exposure. This is not caused by slow aperture movement but by the aperture spring which too strong. The camera can't push it fast enough.

Here is an example with the SMC Pentax-A Zoom 1:3.5-4.5 3-70mm 70mm wide open but hexagonal highlights (a bit vague here).

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06-13-2019, 11:01 AM	#16
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802 Original Poster	Originally posted by stevebrot This trick works on my K-3. Do you know if all models follow this behavior for magnification? Steve My K-5 does so as well (I almost never used live view in the K-5) ---------- Post added 13-06-19 at 20:06 ---------- Originally posted by shardulm "I don't know what I am doing but somehow its K-1s fault..." I do know what I am doing, I don't know what the K-1 is doing stopping down for me to an unspecified aperture

06-13-2019, 11:28 AM	#17
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,202	Originally posted by D1N0 My K-5 does so as well (I almost never used live view in the K-5) ---------- Post added 13-06-19 at 20:06 ---------- I do know what I am doing, I don't know what the K-1 is doing stopping down for me to an unspecified aperture Do you want to see an image on the LCD screen that you can make sense of or not ?

06-13-2019, 11:32 AM	#18
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802 Original Poster	Originally posted by pschlute Do you want to see an image on the LCD screen that you can make sense of or not ? I can make sense of images on the lcd screen with my m42 and m lenses that I can make sense of. I must have super powers.

06-13-2019, 05:00 PM	#19
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,202	Originally posted by D1N0 I can make sense of images on the lcd screen with my m42 and m lenses that I can make sense of. I must have super powers. With those lenses the camera will change the brightness of the screen so that you have an image to focus on. Why it does not simply do that with a modern lens I know not. Try this also. With a modern lens in LV note how it behaves differently between say Av and M. In M it does not stop down the lens

06-13-2019, 05:59 PM - 3 Likes	#20
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by pschlute With a modern lens in LV note how it behaves differently between say Av and M. In M it does not stop down the lens Not wanting to be contrary, but I just spent several hours doing M mode live view work with a KAF2 lens on my K-3 and can confidently report that the lens does do the protective stopdown in bright light and opens up again when things are dimmer. It will also dim the display in tune with the exposure simulation when EC is applied and will balance that against the aperture magic to give a consistent display brightness. The camera will also normalize screen brightness for very bright and very dim subjects, but defers to exposure simulation when that is invoked. When using the aperture ring on a K-mount lens, the camera never does the protective stopdown but will apply exposure simulation based on EC and then only in Av mode. The screen never darkens with aperture change unless stopped down. It will also normalize screen brightness. M42 is similar except that with it exposure simulation works in both Av and M modes with EC. Strangely, this is not particularly confusing in actual use. Steve

06-08-2022, 03:47 AM	#21
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802 Original Poster	I've noticed this can cause problems similar to sticky aperture. The camera can't open up the aperture fast enough for a wide open exposure. This is not caused by slow aperture movement but by the aperture spring which too strong. The camera can't push it fast enough. Here is an example with the SMC Pentax-A Zoom 1:3.5-4.5 3-70mm 70mm wide open but hexagonal highlights (a bit vague here).