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**csa** · 03-22-2015, 09:53 AM

First time I've attempted to use my $20 manual lens! With the lens set at the "P" mode, images were way underexposed. This one is right out of the camera, no PP at all. F8 @250. I'm pretty pleased with my first attempt, using a manual lens. Yes the seller had removed the pin.

So, what is the "P" mode good for?

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**boriscleto** · 03-22-2015, 09:55 AM

The P mode is only for Ricoh film SLRs (and only certain ones at that). And it needed the pin to work...

So to use it with a Pentax DSLR you need to use manual mode and the Green Button to set exposure.

**csa** · 03-22-2015, 09:59 AM

Thanks for that information!

vonBaloney · 03-22-2015, 10:28 AM

Since P mode doesn't work on Pentax DSLRs, it is essentially an extra stop, so on that lens you could consider P as f/22...

**csa** · 03-22-2015, 10:35 AM

Thanks again!

I just tried using the "Green" button rather than the AE-L (to set shutter), and it was underexposed. I can see that there's a learning curve here!

vonBaloney · 03-22-2015, 10:48 AM

Originally posted by csa

Thanks again!

I just tried using the "Green" button rather than the AE-L (to set shutter), and it was underexposed. I can see that there's a learning curve here!

You must be in M mode on the camera or the lens will not stop down ever.

**csa** · 03-22-2015, 11:02 AM

Originally posted by vonBaloney

You must be in M mode on the camera or the lens will not stop down ever.

Yep; I was in M mode.

johndny · 03-22-2015, 11:14 AM

Did you set the camera to allow use of the aperture ring? (Not sure what camera you have, but the below applies to most any Pentax DSLR, with slight menu differences)
Using Older Lenses on PENTAX K-30 | Ricoh Imaging Support

**csa** · 03-22-2015, 11:23 AM

Yes; the camera is enabled to use the Aperture ring. I have two K10's. I followed these instructions, and made all the changes mentioned:

Using Older Lenses on Pentax K10D, K200D, K20D | Ricoh Imaging Support

alamo5000 · 03-22-2015, 11:59 AM

I used to have this lens and it's really pretty darn good. I wrote a review on it in the lens database. You would be well served to get some kind of hood for it but other than that it's a good little lens. An absolute steal for what they cost.

**csa** · 03-22-2015, 12:08 PM

Yes, I read your very informative review of this lens! Thanks so much for taking the time to do it!

One problem I'm having in M mode, the EV scale does not appear in viewfinder, nor in the LCD. How do I get it to appear in the LCD panel? (On a K10D).

alamo5000 · 03-22-2015, 12:14 PM

Originally posted by csa

One problem I'm having in M mode, the EV scale does not appear in viewfinder, nor in the LCD. How do I get it to appear in the LCD panel? (On a K10D).

I wish I could answer but I have never used a K10D.

stevebrot · 03-22-2015, 04:32 PM

Originally posted by csa

How do I get it to appear in the LCD panel? (On a K10D).

There are two ways to do stop-down metering on your camera with K-mount lenses. The first is to use the green button in M mode to take an instantaneous reading. The second is to use the optical DOF preview (on-off lever). Flip the lever to full right and the exposure scale should be visible in the viewfinder.

Now as for the problem with underexposure...I have sad news. The stop-down metering on both the K10D and K20D is not consistently accurate. The reasons are complex and things are greatly improved on the K-7 and newer bodies, but in a word, it sucks. I wrestled with vintage lenses on my K10D for seven years and the short story goes like this:

Tendency is to underexpose at apertures wider than about f/4 and narrower than about f/8. The sweet spot is usually about f/3.5-f/8.
The amount of underexposure wide open with a faster lens (say your Rikenon) may be a much as 4 stops in my experience
Various solutions have been proposed on this site, but none actually work (YMMV)
The pattern varies by lens with some lenses (my Tamron 70-150, for example) behaving in an essentially normal manner
Some lenses may also overexpose at some apertures, but this is less common and is usually not more than 1 stop

The working solution is to chimp* your first exposure for a given aperture and light, change the aperture/shutter speed to compensate, and use those settings until either the subject or the light changes.

Steve

* review in the rear LCD

**csa** · 03-22-2015, 04:41 PM

Steve, thanks for your reply! This definitely helps.

The green button does not bring up the EV scale, however the DOF preview does!

03-22-2015, 04:32 PM	#13
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by csa How do I get it to appear in the LCD panel? (On a K10D). There are two ways to do stop-down metering on your camera with K-mount lenses. The first is to use the green button in M mode to take an instantaneous reading. The second is to use the optical DOF preview (on-off lever). Flip the lever to full right and the exposure scale should be visible in the viewfinder. Now as for the problem with underexposure...I have sad news. The stop-down metering on both the K10D and K20D is not consistently accurate. The reasons are complex and things are greatly improved on the K-7 and newer bodies, but in a word, it sucks. I wrestled with vintage lenses on my K10D for seven years and the short story goes like this: Tendency is to underexpose at apertures wider than about f/4 and narrower than about f/8. The sweet spot is usually about f/3.5-f/8. The amount of underexposure wide open with a faster lens (say your Rikenon) may be a much as 4 stops in my experience Various solutions have been proposed on this site, but none actually work (YMMV) The pattern varies by lens with some lenses (my Tamron 70-150, for example) behaving in an essentially normal manner Some lenses may also overexpose at some apertures, but this is less common and is usually not more than 1 stop The working solution is to chimp* your first exposure for a given aperture and light, change the aperture/shutter speed to compensate, and use those settings until either the subject or the light changes. Steve * review in the rear LCD

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03-22-2015, 09:55 AM	#2
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	The P mode is only for Ricoh film SLRs (and only certain ones at that). And it needed the pin to work... So to use it with a Pentax DSLR you need to use manual mode and the Green Button to set exposure.

03-22-2015, 09:59 AM	#3
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Thanks for that information!

03-22-2015, 10:28 AM	#4
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Since P mode doesn't work on Pentax DSLRs, it is essentially an extra stop, so on that lens you could consider P as f/22...

03-22-2015, 10:35 AM	#5
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Thanks again! I just tried using the "Green" button rather than the AE-L (to set shutter), and it was underexposed. I can see that there's a learning curve here!

03-22-2015, 10:48 AM	#6
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by csa Thanks again! I just tried using the "Green" button rather than the AE-L (to set shutter), and it was underexposed. I can see that there's a learning curve here! You must be in M mode on the camera or the lens will not stop down ever.

03-22-2015, 11:02 AM	#7
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Originally posted by vonBaloney You must be in M mode on the camera or the lens will not stop down ever. Yep; I was in M mode.

03-22-2015, 11:14 AM	#8
johndny Junior Member Join Date: Jul 2014 Location: New England Posts: 45	Did you set the camera to allow use of the aperture ring? (Not sure what camera you have, but the below applies to most any Pentax DSLR, with slight menu differences) Using Older Lenses on PENTAX K-30 \| Ricoh Imaging Support

03-22-2015, 11:23 AM	#9
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Yes; the camera is enabled to use the Aperture ring. I have two K10's. I followed these instructions, and made all the changes mentioned: Using Older Lenses on Pentax K10D, K200D, K20D \| Ricoh Imaging Support

03-22-2015, 11:59 AM	#10
alamo5000 Pentaxian Join Date: May 2012 Posts: 2,962	I used to have this lens and it's really pretty darn good. I wrote a review on it in the lens database. You would be well served to get some kind of hood for it but other than that it's a good little lens. An absolute steal for what they cost.

03-22-2015, 12:08 PM	#11
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Yes, I read your very informative review of this lens! Thanks so much for taking the time to do it! One problem I'm having in M mode, the EV scale does not appear in viewfinder, nor in the LCD. How do I get it to appear in the LCD panel? (On a K10D).

03-22-2015, 12:14 PM	#12
alamo5000 Pentaxian Join Date: May 2012 Posts: 2,962	Originally posted by csa One problem I'm having in M mode, the EV scale does not appear in viewfinder, nor in the LCD. How do I get it to appear in the LCD panel? (On a K10D). I wish I could answer but I have never used a K10D.

03-22-2015, 04:41 PM	#14
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133 Original Poster	Steve, thanks for your reply! This definitely helps. The green button does not bring up the EV scale, however the DOF preview does!

Rikenon 50mm F1.7 "P" lens

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