[yancheelo]

Hi everybody,
I write to ask for help about how to use old lenses which have been mounted on an old Pentax Super A. Today I have tried a Pentax SMC 50mm f1.7 (I think it was a Pentax M lens, with only one pin), and a Tamron 135mm f2.8, gently provided by a colleague of mine.
Both mounted perfectly on my Pentax k-r. I have set manual mode and manual focus, but the display has shown a blinky "F--" and the shutter did not work (I could not take any picture).
Is there any particular setting to be done on a Pentax k-r in order to use old lenses?

Many thanks in advance for any feedback.

Regards,

Y.

[rbryant]

Did you set "Allow aperture setting other than A"to 2?

[yancheelo]

Did you set "Allow aperture setting other than A"to 2?

Thanks for the tip! I think this is the setting missing. I will try again tomorrow (I hope it will help)

THanks,

Y.

[blackcloudbrew]

Some day, I'm going to go through this entire site and count the number of times this question / situation has been asked or written about! Yikes, it has to be thousands of times at least. Why on earth this simple setting 1) eludes most new Pentax users, and 2) is set to the wrong default in the first place by Pentax?

Is it some kind of new user initiation ritual to see if you can decipher the manual? Would it be wrong to have it set to 'allow' as the default? Sheesh this gets tedious seeing yet another confused owner encounter this gotcha.

Ok, ok, I feel a lot better now, sorry for the rant.

[Adam]

Here are the complete instructions: https://www.pentaxforums.com/forums/pentax-lens-articles/110657-how-use-manua...7-k-x-etc.html

[GeneV]

I do wonder why the default is set to not allow manual aperture. I suppose they are trying to protect us from ourselves when using A lenses, but there is such a large number of Pentax owners who use older lenses that I've wondered about this myself.

[GerryL]

Here's another link "stickied" onto the beginner's corner: https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

[Colbyt]

I do wonder why the default is set to not allow manual aperture. I suppose they are trying to protect us from ourselves when using A lenses, but there is such a large number of Pentax owners who use older lenses that I've wondered about this myself.

+1 on that since the primary reason I bought Pentax was that old glass I had in the closet.

The manual does not even address the issue well enough to make it clear what you need to do. Who has time to read 200+ pages when you have a new toy to play with? Seriously!

But, support, is what makes forums great and I will answer that question with a smile every time a new user asks it because some kind soul answered it for me when I asked.

[wasser]

+1 on that since the primary reason I bought Pentax was that old glass I had in the closet.

The manual does not even address the issue well enough to make it clear what you need to do. Who has time to read 200+ pages when you have a new toy to play with? Seriously!

But, support, is what makes forums great and I will answer that question with a smile every time a new user asks it because some kind soul answered it for me when I asked.

It was pretty simple in my Km's manual. I simply went to the appendix, looked up "lens", went to the page directed, and read it.

Notes on [19. Using Aperture Ring]

When [19. Using aperture ring] is set to [Permitted] in [A Custom Setting3] menu, the shutter can be released even if the aperture ring of the DFA, FA, F or A lens is not set to the s (Auto) position or a lens without an s position is attached. However, the features will be restricted as shown below.

That's followed by an image of the actual menu item. That too is then followed by a page detailing the functionality of each type of lens. I'm not sure how it can be any easier to find or clearer in instructions.

Using your camera doesn't require reading the full manual; the index and appendix are there to assist in quickly finding what one needs.

[SteveUK]

I do wonder why the default is set to not allow manual aperture. I suppose they are trying to protect us from ourselves when using A lenses, but there is such a large number of Pentax owners who use older lenses that I've wondered about this myself.

Just picked up K-r yesterday - looks like someone in Pentax is listening, checked this setting immediately as I'd picked up an old 50mm f1.7 on ebay, set to allow non-auto lenses by default.

Very very happy with camera - horrid pictures with 1.7 lens, newbie errors (figured I'd get the best image with it wide open at 1.7 on a fairly sunny afternoon ... black cat is a sickly blue now ... depth of field pretty narrow though I can't even read her name tag !).

[Colbyt]

On a sunny day start at f/11 and bracket a couple each way. Manual without a meter is a learning process. Much like a tadpole with new legs.

[wasser]

Just picked up K-r yesterday - looks like someone in Pentax is listening, checked this setting immediately as I'd picked up an old 50mm f1.7 on ebay, set to allow non-auto lenses by default.

Very very happy with camera - horrid pictures with 1.7 lens, newbie errors (figured I'd get the best image with it wide open at 1.7 on a fairly sunny afternoon ... black cat is a sickly blue now ... depth of field pretty narrow though I can't even read her name tag !).

This may help.

Amazon.com: Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera (Updated Edition) (9780817463007): Bryan Peterson: Books

And this is a bit of a fun site that lets you mess with the settings and see the differences.

SLR Camera Simulator | Simulates a digital SLR camera

There is nothing wrong with f1.7 on a sunny afternoon, nor in photographing your cat. It's all about what you want the image to look like in the end and if the camera is capable of it. As you stated, the DOF was a bit too narrow so, as you probably realized, using a different aperture would have expanded it.

I can think of two likely issues you may have had in exposure of the cat. If the cat took up a significant enough part of the image, then when you metered the camera set itself to overexpose the cat (check out Basic metering in photography | Photography podcast blog and forum - Photography.ca). Another possibility is the camera wasn't capable of the shot. f1.7 is letting in lots of light. When you metered the scene, if the shutter speed was flashing then the camera is telling you it cannot adjust it to what it thinks is needed. The shutter just couldn't move fast enough.

You can simulate this in the Camera Simulator I linked above. Set it to Av, f2.8, and sunny. The shutter flashes 1/2000 because it can't do it. Snap the photo and it's a washed out, overexposed image.

The camera doesn't ultimately know what the best exposure is. Only you know that. It may be able to get it right most of the time, but it's up to you to understand what it's telling you, it's limits, and how to get the best exposure.

[SteveUK]

...
I can think of two likely issues you may have had in exposure of the cat. If the cat took up a significant enough part of the image, then when you metered the camera set itself to overexpose the cat (check out Basic metering in photography | Photography podcast blog and forum - Photography.ca). Another possibility is the camera wasn't capable of the shot. f1.7 is letting in lots of light. When you metered the scene, if the shutter speed was flashing then the camera is telling you it cannot adjust it to what it thinks is needed. The shutter just couldn't move fast enough.....

A more likely issue is leaving the camera on Tungsten White Balance

More to the point of the OP is Pentax Support posting below, not only tells you how to enable shooting with non auto aperture but also setting green button correctly so it will meter the shot for you and set shutter accordingly (set action in M mode to "Tv Shift").

Using Older Lenses with the PENTAX K-x | Pentax Support