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05-06-2019, 11:31 AM - 1 Like   #16
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I have a HELIOS and a JUPITER plus an original Pentax M42 adapter
I always shoot in AV mode and have never had a problem with the exposure
Camera KP and K1

05-06-2019, 05:54 PM   #17
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Thank for the advice guys, I tried and find out I don't even need to touch the green button to re-meter when stop down in Av mode, I can simply shoot straight that's convenient, but I still over exposed a little when stop down pls see the attached image.

The washout area as seen on the camera screen is much reduced in Av mode, so that I can safety reduce half stop to shoot in RAW to get a usable image, but I still don't know what caused the error, the focussing screen, the focal length of the lens, and the angle the light enter the screen may affect the metering , I will do some test with a wide angle lens to find out.

---------- Post added 05-07-19 at 09:18 AM ----------

Right ! those 3D looks and color rendition are hard to find in modern lenses. I happened to own a Contax with 85/1.4 for a short while and the image blown me away, I can't afford the whole line so I dropped and turned to cheaper alternative, since the m42 problem basically fixed I guess I will grab couple 'hot' lenses to try out !

QuoteOriginally posted by luftfluss Quote
Yup, I have a cheap m42 adapter (with the spring removed) on each lens, friction-fit, and that works just fine for me. I've had 2 bad adapters out of a dozen or so. And I know my light and exposure triangle well enough to get workably close exposures.

But, y'know, if you don't shoot fully manual frequently, I can understand why a person just wouldn't want to go through the hassle of m42.


It would be tough to give up my Tak 200/3.5...




---------- Post added 05-07-19 at 09:20 AM ----------

Sorry I reply via cell phone and seems to have messed up the message format...

QuoteOriginally posted by lotech Quote
Thank for the advice guys, I tried and find out I don't even need to touch the green button to re-meter when stop down in Av mode, I can simply shoot straight that's convenient, but I still over exposed a little when stop down pls see the attached image.

The washout area as seen on the camera screen is much reduced in Av mode, so that I can safety reduce half stop to shoot in RAW to get a usable image, but I still don't know what caused the error, the focussing screen, the focal length of the lens, and the angle the light enter the screen may affect the metering , I will do some test with a wide angle lens to find out.

---------- Post added 05-07-19 at 09:18 AM ----------

Right ! those 3D looks and color rendition are hard to find in modern lenses. I happened to own a Contax with 85/1.4 for a short while and the image blown me away, I can't afford the whole line so I dropped and turned to cheaper alternative, since the m42 problem basically fixed I guess I will grab couple 'hot' lenses to try out !

Last edited by lotech; 10-24-2019 at 10:22 PM.
05-06-2019, 09:32 PM - 1 Like   #18
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My m42 lenses got a revival after I got a Sony A7. It is not a perfect camera but for use with old MF lenses it is nice IMO.

My main system is still Pentax K3II with AF lenses, but A7 feels like it was designed for old MF lenses.
+ Good focusing aid with large EVF in a compact form factor. It is almost like going back using an old manual focus film SLR.
+ No crop factor make most of the lenses more valuable to use for me.
+ No trouble with metering.

So now I will try to hunt down more of the early m42 Takumars from late 1950s, because I really like how many of them capture the scenes.
I just got hold of an Auto-Takumar 55/2 with no visible signs of usage, which is nice for a 60+ year old lens.

I miss sensor stabilisation on A7, but on the other hand it would make camera heavier, and with electronic shutter it is possible to use quite long shutter speed anyway.
05-07-2019, 12:02 AM   #19
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I don't use Sony but owned couple Fuji before, the XE2 is very nice for adapting lenses too, I specially like the Fuji is the great IQ at high ISO up to 6400. the K3 is max at 1600-3200 before the image turn bad, auto white balance is excellent on the Fuji even at low light when compare with the K3, but I don't like the handling and menu design of the Fuji and gave up.

05-07-2019, 12:27 AM   #20
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Hi lotech

QuoteOriginally posted by lotech Quote
so that I can safety reduce half stop to shoot in RAW to get a usable image,
You assured that your exposure steps are still set to 1/3 stop increments (default setting) and not to 1/2 stop increments.
Just to be sure.

KR, Ron
05-07-2019, 12:32 AM   #21
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QuoteOriginally posted by lotech Quote
Thank for the advice guys, I tried and find out I don't even need to touch the green button to re-meter when stop down in Av mode, I can simply shoot straight that's convenient, but I still over exposed a little when stop down pls see the attached image.

The washout area as seen on the camera screen is much reduced in Av mode, so that I can safety reduce half stop to shoot in RAW to get a usable image, but I still don't know what caused the error, the focussing screen, the focal length of the lens, and the angle the light enter the screen may affect the metering , I will do some test with a wide angle lens to find out.

---------- Post added 05-07-19 at 09:18 AM ----------

Right ! those 3D looks and color rendition are hard to find in modern lenses. I happened to own a Contax with 85/1.4 for a short while and the image blown me away, I can't afford the whole line so I dropped and turned to cheaper alternative, since the m42 problem basically fixed I guess I will grab couple 'hot' lenses to try out !



---------- Post added 05-07-19 at 09:20 AM ----------

Sorry I reply via cell phone and seems to have messed up the message format...
The image illustrates what I said, yay wide open=dark, closed down=bright. Try +2 wide open, decreasing incrementally to +1 for shut down
05-07-2019, 02:25 AM   #22
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Yes I set to 1/3 the first day I receive the camea thanks

QuoteOriginally posted by Zijspoor Quote
Hi lotech

You assured that your exposure steps are still set to 1/3 stop increments (default setting) and not to 1/2 stop increments.
Just to be sure.

KR, Ron


---------- Post added 05-07-19 at 05:26 PM ----------

Right I will play around with it thanks !

QuoteOriginally posted by Cerebum Quote
The image illustrates what I said, yay wide open=dark, closed down=bright. Try +2 wide open, decreasing incrementally to +1 for shut down
05-07-2019, 07:02 AM   #23
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a very long time ago now, i posted the following



the metering of DSLRs using non A lenses is not great, it seems to be dependent on the F Stop used when actually taking the metering reading. as all kit lenses and consumer lenses are typically F4-5.6 this is where metering is actually accurate.

you ned to know how your particular body (model) actually behaves to use the lenses effectively.

i have not done a lot on this since my K7 days, because i really only use manual non A lenses actually on my K10 and *istD

the way to do a test is to find a uniform color and illuminated surface, i like paved roads or block walls, and to check metering at each aperture.

note that 128 greyscale is correct exposure and each ~40 greyscale is 1 stop


Last edited by Lowell Goudge; 05-07-2019 at 08:24 AM.
05-07-2019, 09:27 AM   #24
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That's interesting thanks for the info., the exposure peaks at around f8-11 aligned with my finding, what is the setup you used to produce the middle green line that quite flat overall ?
05-07-2019, 09:45 AM   #25
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QuoteOriginally posted by lotech Quote
That's interesting thanks for the info., the exposure peaks at around f8-11 aligned with my finding, what is the setup you used to produce the middle green line that quite flat overall ?
The middle green line is an A series lens. Although not stated by Pentax, what many forum members (self included) believe, is that Pentax compensate for the native aperture of the lens, relative to F5.6 and the specific camera model in question.

This way using the known maximum aperture reported through the lens contacts, they give reliable open aperture metering . Where this first got picked up was using the K10 and a teleconverter that simply feeds through the native lens aperture, on my sigma 70-200/2.8

Using a 1.4x TC the true aperture was F4 but the camera reads F2.8. As a result it always over exposed.

You need to plot the performance with your body as I have not tested (don't own) a K3. If you shoot at F11 often, and you know the variance between greyscale values for f5.6 and F11 you can calculate the compensation needed. Or, conversely, if you have a medium grey surface like a tree trunk, or pathway, meter off it and set your exposure to centre the peak of the histogram. The graph just lets you work it out in advance
05-07-2019, 05:51 PM   #26
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Thanks for the detailed info. there is a lot to learn, like the old days bring a grey card and light meter would be much easier, digital actually make things complicated to use ! the only good thing is RAW there is room for adjustment.

QuoteOriginally posted by Lowell Goudge Quote
The middle green line is an A series lens. Although not stated by Pentax, what many forum members (self included) believe, is that Pentax compensate for the native aperture of the lens, relative to F5.6 and the specific camera model in question.

This way using the known maximum aperture reported through the lens contacts, they give reliable open aperture metering . Where this first got picked up was using the K10 and a teleconverter that simply feeds through the native lens aperture, on my sigma 70-200/2.8

Using a 1.4x TC the true aperture was F4 but the camera reads F2.8. As a result it always over exposed.

You need to plot the performance with your body as I have not tested (don't own) a K3. If you shoot at F11 often, and you know the variance between greyscale values for f5.6 and F11 you can calculate the compensation needed. Or, conversely, if you have a medium grey surface like a tree trunk, or pathway, meter off it and set your exposure to centre the peak of the histogram. The graph just lets you work it out in advance
05-07-2019, 06:16 PM - 2 Likes   #27
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QuoteOriginally posted by lotech Quote
Thanks for the detailed info. there is a lot to learn, like the old days bring a grey card and light meter would be much easier, digital actually make things complicated to use ! the only good thing is RAW there is room for adjustment.
For years, even with an advanced film camera like the PZ1 I would work in manual mode, and meter off the road, or a tree trunk, and just leave the exposure alone until lighting changed. I consider things like the road to be a greycard
05-07-2019, 07:15 PM - 2 Likes   #28
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So I have a few m42 lenses that I use along with some manual focus no electronics K mount lenses. So here's a few thoughts.

1. If I'm shooting where things are moving then I don't use manual focus. I use m42 if for meditative shooting with lots of time to think what you want to achieve, take test shots and then get it right. I do this for modern Pentax lenses too if I have the time. Exposure is rarely where I want it. I watched a very good wedding photographer do this with some Canon pro gear. No shame in chimping.

2. Very few lenses have light bleed issues with a flush mount. Mostly Helios lenses and some random antiques. It's easy to fix with tape. I would not give up infinity focus with a flange mount although frankly I and probably most everyone else use their m42 lenses wide or nearly wide open where infinity is sort of irrelevant.

3. It is nice to use a dedicated m42 camera and if you've got a not worth fixing ACB failed K30 or K50 this is a no brainer. There are probably lots of them kicking around on this forum if you ask in the Wanted section.

4. There are a significant number of lenses that need to have their push pin depressed in order to allow stopping down, mainlyl the Russians and East Germans. It's either surgery, super glue or a flush mounted adapter that has an inner ring to depress the pin. I've got one of the latter, but it's permanently stuck on my my K30 which is not a problem for me but would be for some others.
05-08-2019, 07:20 PM   #29
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I don't have any issues with M42 lenses. In Fact my problem is the opposite using new AF lenses....lol
05-10-2019, 10:33 AM - 1 Like   #30
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Establish a plan for the camera & lens combo to always have an underexposure. You can pull highlights from darker underexposure, but can't put back blowouts. Worst scenario would be shoot 3 shot exposure brackets at +2, 0, -2. I use the "green" button, but a lot of times I have a feel from having learned manual film exposure that what I'm seeing is too slow shutter speed, so I quickly adjust shutter speed higher manually, and check histogram. Using Manual, or Av, setting, set ISO, choose f-stop, set reasonable SS, and take test shot, then adjust for underexposure; or use Green button, take test shot, and adjust. IF shots need to be quick, set up for the area foliage, light, shadows, etc, then pre-focus for middle range in area, when subject arrives refocus and shoot. If you pre-set off a mid-tone gray tree trunk, sidewalk, rock, or whatever, you have a chance with underexposure to lift highlights in post production. You can't put back blowouts.

Lowell is right, most tree trunks, roads, or large rocks, will give you a reasonable "Gray Card" to use.

With modern lenses, TAV, or Av, with set ISO or an autoISO range set, can give you semi-manual control. You still have to have a feel for the lens-camera relationship.

If nothing else, start each session with a few "learning " shots to get a feel for on the fly adjustments.

I look at cameras and lenses as tools. I don't expect a microchip to do my job. If I did I would shoot modern lenses on Auto or "P" and bitch about my equipment.

Sorry about rambling,

JB
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