[LightMeter]

I was wondering if ALL Pentax DSLRs will meter with older lenses. I have Nikon D300 and am looking to get a second body. But the least expensive Nikon that has this capability is 1200usd. Will I have that problem if I switch over to Pentax? Does Pentax have the best backward compatibility?

[jac]

No and yes to your two questions. Lots of links to metering older manuals but here's the official Pentax version.

Q: Can I use older PENTAX lenses on my K-x?
support.pentaximaging.com/node/1

Lots of fantastic M's from the manual days out there at give-away prices. I still use a couple of lenses which I got new in the seventies.

[richard balonglong]

Yes. All Pentax DSLRs can meter any manual lenses by using or activating the optical preview. With my Pentax *ist DS, K110D, and K-7, I can meter with all of my old manual lenses, same too to other Pentax models. =)

[audiobomber]

I was wondering if ALL Pentax DSLRs will meter with older lenses. I have Nikon D300 and am looking to get a second body. But the least expensive Nikon that has this capability is 1200usd. Will I have that problem if I switch over to Pentax? Does Pentax have the best backward compatibility?

All Pentax cameras will mount any lens ever made for Pentax cameras (i.e any K-mount lens). There are a few of the oldest cameras (K100D and older) that cannot focus new SDM lenses (in-lens motors).

All Pentax bodies will meter manual lenses in Manual mode. You set the aperture on the lens and push the appropriate button (usually called the Green Button, but it's not green on the old bodies). Matrix metering isn't available but center-weighted and spot metering are.

If you take a photo with a manual lens in any mode other than M, the camera takes a photo with proper exposure, but the aperture will not close down, so the photo is always taken wide open, regardless of where the aperture ring is set.

The above relates to bayonet mount lenses. I don't know whether this applies to old screw mount lenses, I don't own any.

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Last edited by audiobomber; 09-10-2011 at 06:59 AM.

[boriscleto]

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html

Manual focus lenses with the A setting will work in all modes and can use Matrix and Spot metering.

Non-A lenses work in M mode with stop down (center weighted) metering. AV mode can be used but the lens will be wide open.

Screw-mount lenses (with appropriate adapter) can be used in M mode with stop down metering or in AV mode. The disadvantage of screw mount lenses is that you can't use open aperture metering. Stopping down the lens makes the viewfinder darker.

[Lowell Goudge]

Just to be clear

KA mount lenses SMC-A or third party equivalent lenses will operate in all exposure modes on every DSLR body

K mount lenses SMC-M or SMC pentax lenses will allow metering manually in stopped down mode using the DOF preview or will set the shutter speed to match the aperture in manual mode withthe green button, but will only work in manual mode and give spot or center weighted metering not matrix. On bodies later than the *istDS2 cannot be used in flash mode

[freddykrueger]

I can't believe I've missed this "Note: pressing the Exposure Compensation button (the +/- button) on the K-x will automatically set an appropriate shutter speed in Manual exposure mode when using non-"A" series lenses."
I have always used the green button to measure the exposure and I was sad I couldn't use the DOF preview. Not any more!

[RioRico]

And a little more: A Pentax dSLR will meter with ANY lens mounted on it.

An AF or A-type MF bayonet lens has interactive automatic aperture control.
An M- or K-type MF bayonet lens has mechanical stop-down aperture control.
A screwmount or other adapted MF lens has only manual on-lens aperture control.

But ANY lens will meter and shoot in Av (aperture priority) or M(anual) mode.
This includes N/AI, OM, C/Y, and other lenses chopped to force-fit on PK mount.

Some dSLRs (K10D, K20D) may not meter accurately with some MF lenses.
But such metering quirks, once known, can be easily compensated for.
Pentaxians worry more about aperture control than metering issues.

[LightMeter]

Ok thanks for the posts. I'm kinda annoyed at Nikon's "crippling" the less expensive bodies. The D50 I had before did not meter with manual lenses. Some of the film bodies I've had in the past did not either. And now the less expensive DSLRs don't even AF with the old AF lenses-only AF with the lenses that have the motor in the lens. At least they didn't change the mount like Canon did. If I do get a Pentax DSLR, it won't be until next year-just dropped alot of $$$ on a 645 and 2 lenses