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02-12-2016, 04:17 AM   #1
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Old prime lens on K-r - getting a shutter speed reading

Hi all

Firstly, I should say that an immensely kind Pentaxian sent me two prime lens for free all the way from the US to the UK. Proof if ever needed that the Pentax community is amazing. I'd happily name him, but I suspect he's modest!

I thought I'd got to grips with using the 50mm SMC Pentax A on my K-r. In manual mode, setting the aperture, focusing, adjusting ISO and pressing the green button to do stop down metering.

I've just offered to take photos for a Malaysian meal night my friend is doing at her new cafe tonight.

I've just been practising with the lens. Whenever I press the green button I get a shutter speed of 1/30 secs. This is in various light conditions and at everything from f2 to f22.

I hit the exposure compensation button by mistake and then it read 0.5 secs whatever I change.

I suspect the exposure compensation button is somehow overriding things.

If anyone can offer any help, I'd be massively grateful. I really would like to use the prime tonight and have told my friend I'll do it!

Thanks


Si

02-12-2016, 04:28 AM - 1 Like   #2
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Exp comp doesn't work in M mode (since you're in complete control, there's no compensation the camera should account for when calculating, because it's your duty to set everything).
Are you sure you configured the green button for stop-down metering? it's in the menu, button settings.
Are you using the A position on the lens and setting the aperture via the camera?
If you're not, did you check the allow aperture ring custom setting in the menu?
02-12-2016, 04:29 AM - 1 Like   #3
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For SMC-A lenses you set the aperture ring to the A position and you can shoot any mode of the camera, the only thing that does not work, obviously is AF.

When you turned the camera on it should prompt you for focal length, this is to set the shake reduction for the focal length because the lens does not do that for you.
02-12-2016, 04:30 AM - 1 Like   #4
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is you mode dail on M when using the green button?

and if it's an A version, no need to use the green button. Put the mode dial on AV and dial in the f stop on the body..

02-12-2016, 08:11 AM   #5
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Hi guys

Thanks so much for the replies.

Sorry, I kinda confused things by talking about the exposure compensation button - I wasn't using it in when in manual mode. I just happened to press it by mistake and it seemed to change things shutter-speed wise.

I think I've sorted it. I have shot using the lens before and imputed focal length etc. the comment from lens-beginner got me going back to the green button settings. Turns out it was no longer on Tv shift - I believe that's the correct setting. I'm sure it must have been on that before - I looked at the EXIF data and the shutter speed varies in the shots. I just have changed it somehow.

It seems to work as exoected now.

I haven't been using it on the A setting for aperture. This thread has prompted me to look into that.

I had no idea you could use this lens in AV mode. That'd be great as I generally use that mode a lot.

Thanks everyone - I did read a guide on this, but don't think it mentions the TV-shift selection - I've seen that somewhere else I think. I probably should have researched a bit more, but I panicked slightly, as it's a busy day and I have this "shoot" tonight!
02-12-2016, 08:21 AM   #6
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As Grispie noted, there's no need for green button metering with an A lens. Set the lens to the A position, then set your aperture on the camera (not the lens itself), focus and shoot. Green button metering is used on M and K series lenses, which have no elecrrical contacts to communicate with the body.
02-12-2016, 08:39 AM   #7
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Thanks Paul - this is very much a learning curve for me!
02-15-2016, 01:27 PM - 1 Like   #8
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Think about "Av" (aperture priority) as being the opposite of "Tv" (shutter priority) of each other (and vice-versa) i.e.:

Av = YOU set aperture first (==> it's the priority), then the camera controls the shutter speed based on its measurement of light.

Tv = YOU set the sutter speed first (again, ==> it's the priority), then the camera controls the aperture/opening based on light.

I guess earlier, you were in Tv mode, so even though you didn't realize it, you set the shutter speed and then the camera just chose the aperture for you based on light.


You'd want to pick one of the modes (Av or Tv) based on what you're trying to do.

For instance, if you want to take a pic with a lot of bokeh in the background, you will want the lens wide open and to stay wide open, so you'd use Av mode and set the lens wide open, then let the camera control the shutter speed.

On the other had, if you were shooting something with a lot of movement , you'd want the shutter speed to be fast, to freeze the motion, so you'd set the mode to Tv and set a high shutter speed, then let the camera control the aperture.

Or something like that !!

02-16-2016, 08:15 AM   #9
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Thanks ohaya - useful information.

Actually, I think the problem was that the green button wasn't on TV-shift. However, I'm often accidentally in shutter speed priority because the mode dial has shifted position, so it's good advice.

I meant to come back to this thread and say that the event went very well and the owner loved the photos. The advice here was very helpful with that. The lens provided to me by a fellow Pentaxian was a joy to use!
02-16-2016, 09:50 AM - 1 Like   #10
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QuoteOriginally posted by Popty Ping Quote
Thanks ohaya - useful information.

Actually, I think the problem was that the green button wasn't on TV-shift. However, I'm often accidentally in shutter speed priority because the mode dial has shifted position, so it's good advice.

I meant to come back to this thread and say that the event went very well and the owner loved the photos. The advice here was very helpful with that. The lens provided to me by a fellow Pentaxian was a joy to use!
You're welcome and that (the dial changing) seems to happen to me too sometimes, but you should be able to see the difference on the LCD, e.g., if you are in shutter priority, it'll let you set the shutter speed with the wheel thing, whereas if it's in aperture priority, it would let you set the aperture. Of course, that only helps if you're paying attention to the LCD screen, which oftentimes is not the case (for me, at least !!).

Glad it worked out for you.

Later,
Jim
02-17-2016, 01:17 AM   #11
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That's my problem Jim - I often don't pay attention to the LCD!

I do wonder whether a means of locking the wheel in one position might be a good idea for a camera. Maybe some do and I've just not seen them (I've used very few dSLRs).
02-17-2016, 01:30 AM - 1 Like   #12
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QuoteOriginally posted by Popty Ping Quote
That's my problem Jim - I often don't pay attention to the LCD!

I do wonder whether a means of locking the wheel in one position might be a good idea for a camera. Maybe some do and I've just not seen them (I've used very few dSLRs).
I seem to recall that, in the old days, on cameras like the Pentaxes, you had to lift the dial up slightly before you could turn the dial. But the K-r I have doesn't have that... it just turns.
02-17-2016, 01:32 AM - 1 Like   #13
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QuoteOriginally posted by Popty Ping Quote
do wonder whether a means of locking the wheel in one position might be a good idea for a camera. Maybe some do and I've just not seen them (I've used very few dSLRs).
yes, K3 has for instance.
Useful.
btw, i recently bought a kr next to my k3. It is a very nice little camera..
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