[fra-zzr]

Exactly what "old 50mm prime" did you get? Different mounts require different methods to operate them.

its an 'smc pentax-m 1:2 50mm' ? does that help

[wasser]

Yes! It absolutely does. There are several different mounts and each behaves differently. You have an M series. With this type of lens you have to turn the aperture ring on the lens to change the aperture. Make sure you both meter and take the shot with the lens at the aperture you desire.

Also, be sure the aperture blades actually move on the lens.

BTW, in my link above, the author apparently has two of those lenses for his *ist DS.

[Recercare]

If I set aperture using the aperture ring, hit the green button to meter, take the shot, then shoot a different frame with the same aperture.....then what's the point in hitting the green button before the second shot?

Kind regards
.lars

[wasser]

If I set aperture using the aperture ring, hit the green button to meter, take the shot, then shoot a different frame with the same aperture.....then what's the point in hitting the green button before the second shot?

Kind regards
.lars

None...at least possibly. As long as the lighting conditions are constant, then the nothing need be changed.

[Recercare]

I just did another test, I hit the green button and the shutter speed was set to 1/8s...which resulted in an overexposed picture. I adjusted the shutter speed to 1/30s and the exposure was spot on, then I hit the green button again and the shutter speed was set to 1/8s again......what's that all about?

Kind regards
.lars

[wildlifephotog]

The camera is wanting to underexpose. Don't test using indoor lighting ( tungsten ).
What metering pattern are you using? Center weighted usually works the best.

[wasser]

Recercare, what camera and lens are you using? I have a Km/k2000 which meters correctly in manual. However, it underexposes in Av (+2EV).

I don't have one, but I've read about metering issues with the K20D and K10D with pre "A" lenses.

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Last edited by wasser; 09-04-2009 at 01:23 PM.

[Rockdoctor]

Recercare et al.

It's all quite simple with the M lenses.

1. Set your desired aperature.

2. Press the AE-L or Green buttons. The LCD will indicate the appropriate Shutter speed for the given aperature. If is the shutter speed is too low for hand held shooting, use a tripod or increase the film speed and go back to step 1.

3. Focus and shoot.


You will find with some lenses that the camera doesn't actually pick the perfect shutter speed. Often I will take a shot based on the camera's selected shutter speed, review on screen and perhaps increase or decrease the shutter speed and or decrease or increase the aperature(increase or decrease f-stop) and shoot again. I get the best results with this method.

[Marc Sabatella]

I just did another test, I hit the green button and the shutter speed was set to 1/8s...which resulted in an overexposed picture. I adjusted the shutter speed to 1/30s and the exposure was spot on, then I hit the green button again and the shutter speed was set to 1/8s again......what's that all about?

Tough to say without seeing the picture. One thing to realize is that with manual lenses, your camera cannot use the regular multi-segment metering. it automatically changes you to center-weighted metering mode. So it is unable to, for instance, protect against blowing out an isolated highlight. That in itself could be accounting for the overexposure you are seeing. But also, the K10D and K20D are known to have issues with Green button metering that make them tend to expose worse and worse (usually overexposure) the farther you get from wide open on the aperture.

[Canada_Rockies]

Try setting the exposure using the Sunny 16 rule. Here it is in a nutshell.

Set the shutter speed to the ISO setting of the camera, and set the aperture as follows with the camera mode dial set to M for manual:

• Bright sunny day, normal subject f/16 (hence the name of the technique)
• Bright sunny day, snow/beach scene f/22
• Bright cloudy day, f/11
• Shade or darkish clouds f/8
• Really dark day f/5.6

If these don't give you correct exposure, there is something seriously wrong with the lens. It is not stopping down quickly enough for the exposure.

[Recercare]

Thanks everyone

I tried again, first outdoors and the exposure was almost spot on. Then I tried a couple of shots indoors again and it was also quite good. I don't know what happened earlier today with the gross overexposure but it works fine now

The combo is k10d + smc-m 135mm F3.5.

[Canada_Rockies]

Thanks everyone

I tried again, first outdoors and the exposure was almost spot on. Then I tried a couple of shots indoors again and it was also quite good. I don't know what happened earlier today with the gross overexposure but it works fine now

The combo is k10d + smc-m 135mm F3.5.

I'm glad it worked out for you. I'm still using a pair of M lenses, and am very pleased with them.

[Recercare]

I purchased the 135mm F3.5 to test if a full manual lens would work for me. Well, it does....I don't find manual focus/exposure that difficult. IQ-wise it's a fine lens, it's just that I am spoiled with the DA 40 and DA 70. However, I will be looking out for the M* 300 and A* lenses now that I know I can manage without AF.

I know the 50mm F1.7 lenses are good but what about the 150-300mm range ?

Kind regards
.lars

[Marc Sabatella]

The M200/4 is more or less like the 135 - pretty good, not outstanding compared to modern lenses, but a stop faster than most other affordable options. However, the M135.3.5 wins over a lot of other options not only on account of speed but also size. The 200/4 does *not* have that advantage over the typical zoom that covers that focal length.

[Recercare]

So apart from the 50mm F1.7 it's only the M*300mm that really compares to the DA* or DA Ltds ?