Which 50mm Lens?

Hi all, I'm new here (please be gentle!)

I am looking for a lens that will allow me to take some nice portrait shots indoors with relying on the flash so much and a fast 50mm lens seems at first to be a sensible option, is it?

There is a choice of course..

M 50MM F1.4 - £50 Used
M 50MM F1.2 - £?? Used
M 50MM F1.7 - £30 Used
FA 50MM F1.4 Lens - £150 New (SRS)

Is it simple as that or am I barking up the wrong tree all together?

Any advice will be appreciated

Simon

Welcome!

What camera are you planning to use the lens on?

There are also the A-Series 50s, the commonest being the F2 and F1.7, though there's also the F1.4, and, I believe, the extremely rare F1.2.

Indeed there's lots of lens info here.

Possibly more than you wanted!

But it would be best if you told us what camera you're using first, and then advice will be easier to give.

Personally, I'd forget the M series lenses if you have a Pentax DSLR other than the *istD or *istDS.

For lenses that should last you a lifetime, barring accident or other misfortune, stick to the SMCP-A series for manual focus, SMCP-F or FA for auto focus.

An SMCP-A 50mm 1:1.7 would be a good one to start with. The SMCP-FA 50mm 1:1.4 is a dream and is my best recommendation depending on your budget.

You maybe just missed a bargain 43mm Limited lens from JohnMcD for £165. He's the guy with a faulty camera, so he's selling off all of his expensive lenses .

Sorry for my lack of info, I got a bit carried away!

Primarily the lens will be used on K10D, but if I could use it on ether of my Manuals SLR's (MZ-7 & K1000) it would be nice!

Thanks for your rapid responses - there is plenty of reading to be done!

Definitely forget K or M series lenses then. Get A-series or later, and if the lens has an aperture ring, set it to 'A' and on the K10D, set the aperture from the body.

Thanks for your advice, it is very appreciated - It was my intention from the start to go for a newer lens - but I had read favourable things about older lenses.

I am not the most experienced Pentax user around, so could you explain to me why a M series lens wouldn't be advisable? I have read that they fit my cameras (link) but are there some performance issues?

Thanks Again

Simon

Be aware that the SMCP-A 1:1.7 has a badly designed mount for the spring in the aperture ring, and these can, and do, fail.

I have owned three of these lenses, and one has failed. There have been many other examples, though I don't think the general failure ratio is anything like as bad as my experience.

G

They fit perfectly well physically, and if you want to do your own exposure calculations and use the camera in manual mode they're fine.

But on the K10D give they rise to exposure errors at any aperture other than wide open for a given lens.

This is because the camera has no way of knowing what the aperture ring is set to, on a lens old enough to have one.

So to take a meter reading with the aperture set to anything except wide open, it has to stop the lens down, meter the light, and then set an appropriate shutter speed for whatever the aperture happens to be. For reasons no one ever seems to have got to the bottom of, it overexposes, and the smaller the aperture, the more it overexposes.

If you search the forum for "stop down metering" you'll find a number of threads discussing this.

There are no such issues with A-series lenses (set to A) or later, since the camera can set the lens' aperture itself, without relying on the aperture ring. Therefore all metering is done with the lens wide open.

They fit the K10D and are optically good, but they can hardly be used with the camera's automatic and semi-auto exposure modes, nor even used reliably with the manual mode without some extra hassle or luck. This is to do with the lack of communication between the lens and the camera, and design issues with the camera.

Some of the M and K lenses are worth buying for your camera because there are no cheap modern equivalents of the same speed and quality. M 100mm F2.8 and K SMC 135mm F2.8 are a couple of examples.

But since the A 50mm 1.7 is so common, good and fairly cheap, there is not much point in getting an M 50mm to use with a modern camera at all.

Thanks ChrisA, that makes sense!

Although I use the camera on manual mode, I rely on the light meter within the camera (I do have a hand held light meter - not a very good one though!) So a M lens sounds like it will cause me problems!

Thanks for all your help, I will let all you know how I get on with some images from my forthcoming holiday!

Cheers all

Simon

There's only one to get. The Bigma!
(Sigma 50-500mm zoom)
cheers
bb2

Its not all black and white
I have learnt a lot using M lens with the K100D

Just got my first A lens, a 50mmf1.7
Must admit it is great to stick it in Av and control aperture from the body
cheers
Pete

My understanding is that the K100D doesn't suffer the same stop-down metering issues that the K10D does.

I don't have one, though, so I can't confirm this.

Even on the K10D, if you meter with the lens wide open, and then calculate the shutter speed yourself for some other aperture you set with the aperture ring, it'll be fine.

Just less convenient, as you say.

Those of us who remember cameras which didn't have coupled exposure meters do not find M lenses too difficult to use, though in fast-moving situations the A lenses are obviously advantageous.

If you are shooting in a studio, where you are in manual mode anyway, there is no disadvantage to K or M lenses at all.

KEH are currently selling an M 100 2.8 for $119.00.

G

Having just re-read your original post, I am reminded that you are talking about a lens for indoor portraits.

In this situation, use manual flash and a manual K or M lens. Simple.

G