Pentax Lenses for Dummies

Hi all,
I have just bought today my first Pentax (k100d super, on this forum) so forgive me my silly questions and lack of understanding. I would like to ask you for a quick and simple explanation of pentax lenses' symbols and what I can put onto my k100d and what I cannot.

Especially I was looking at 50mm 1.7 and seen 50mm-A and 50mm-M :/ Confused.

Thanks a lot.

Both will work. You will need to change the aperture ring setting to "allow" the manual setting, but that's it.

Bret

Buy the A version, it'll make life much easier!

Optically the lenses are identical. The M series lenses are earlier fully-manual lenses from the days when the aperture was set with the ring on the lens, the A are slightly later and feature the ability to have the camera body set the aperture (with aperture ring set to "A").

M series or earlier lenses on a DSLR require you to use Aperture priority or Manual modes, the former will meter and shoot with the lens set to its widest aperture while the latter can be a bit hit and miss in getting a good exposure. A series lenses will allow you to use all the modes apart from (obviously) Auto focus, as well as enabling the camera to report the aperture in the viewfinder and on the LCD.

Any K mount lens will fit and work, however the A series ones are more flexible.

Brilliant Matt, this is the kind of answer I was looking for Thanks to you Bret as well.

Weirdly I wouldn't actually want to use my Pentax-A 50mm manually, as the aperture ring is plastic and doesn't feel anything like as precise as the M series version. On a DSLR that doesn't matter as you're setting the aperture via the camera body rather than directly on the lens. Just set it to A and treat it like a modern lens.

Here's a brief run-down on using manual K mount lenses on a DSLR (M or K series):

Go into your camera menu and set "allow aperture ring" (not sure of the exact wording)

Fit the lens, switch to manual focus and select Av or M mode.

When you switch on, the camera will prompt you to set the focal length of the lens so that the shake reduction can function properly. Just dial it in and press ok, this step also applies to A series lenses.

If you're in Av mode then the aperture setting on the lens doesn't matter. The camera will meter and shoot with the lens held at its widest aperture, regardless of what you set.

In M mode the aperture ring does make a difference, but you need to press the green button (or +/- button on some bodies) to have the camera stop the lens down and take a reading.

It does have uses, I've tested M series lenses on digital before using them with film to make sure that they don't have any problems and I do have a Pentax-M 135mm that I intend to use regularly with my K-m. But I try to stick to A series primes - now have 28mm, 50mm and 200mm lenses.

Manual zooms are a bit of a pain due to the need to set the focal length for the shake reduction, obviously when you zoom this will change but the camera won't know unless you switch off, on, and set the new length!

I have saved this thread for future reference Many thanks for this Matt.

SMC - Super Multi Coated - If the lens doesn't have these letters on it, it will be multi coated, but will not have the benefit of the superior SMC coating.

Early screw threaded Takumar lenses are highly regarded but Pentax reused the name Takumar on some budget K mount lenses which are not SMC coated.

M42 screw mount lenses can be used on K (bayonet) mount cameras with an adapter. If you go this route, invest in the Pentax adapter to guarantee focus at infinity.

The earliest K mount lenses have no suffix but are generally referred to as K series.

These were followed by lenses having the M suffix, as in SMC Pentax-M. These are fully manual lenses and have no A setting on the aperture ring. These lenses, together with Mft and K series lenses, can only be used stopped down on a Pentax DSLR when the body is set to Manual exposure mode. In all other modes the image will be exposed at full aperture.

SMC Pentax-A series came next. These lenses have the A setting on the aperture ring allowing the aperture to be set on suitably equipped camera bodies. Setting the lens to A and setting the aperture on the camera is the recommended way of using these otherwise the same restrictions apply as M series lenses and earlier.

AF lenses were then introduced having the suffixes F and FA as in SMC Pentax-F. These lenses also have the A setting on the aperture ring and is the recommended setting for Pentax DSLR's.

The first AF lenses having no aperture ring had the suffix FA J.

Then came the digitally optimised range, DA. These have no aperture ring and the aperture must be set on the body.

D-FA lenses are digitally optimized but have an image circle to suit 35mm cameras.

Most of the above lens ranges also include a number of models with a 'star' suffix. These are highly prized lenses, made by hand in Japan, and are of the highest optical and mechanical quality. They are also very expensive.

The FA and DA ranges also have a number of lens models designated 'Limited'. These are manufactured to a very high optical and mechanical standard and are also expensive.

Until recently the focus mechanism employed a camera body mounted motorized screw drive. Pentax are now utilizing a lens mounted drive motor designated SDM, or Supersonic Direct drive Motor. Most SDM lenses also have the legacy screw drive mechanism but some newer models like the DA* 55mm 1:1.4 SDM lens has this omitted and is therefore SDM only, or manual focus.

That's about it I think. You can research lenses further here.

EDIT: Thanks Stefan.

Even if someone write something more I can't take it any more today Quality information! Now I am ready for a lens hunt
Thanks

Peter you've SDM wrong it stands for Supersonic Direct-drive Motor
I know I'm the worst some time

Also it's easier to copy paste from the Pentax site btw link

Here is a link to helpful site about K-mount lenses, I've linked you to the Terminology link

C'mon, we've only just got started.

There are 'soft' lenses, tilt 'n shift lenses, constant aperture zooms, quick shift manual focus, power zoom lenses . . . .

OK, I'll stop now.

Thanks Stefan, edited. I have spent hours on Boj's site and I've never seen that page before.

Cut 'n paste doesn't cement the knowledge into my little grey cells though. It could also be copyright theft.

Thanks for the links.

There were also a handful of Pentax-branded zooms without SMC coatings - I think there were A and F versions of 28-80mm and 70-210mm without it. I have one of the Pentax-F 28-80mm lenses which is ok - solidly made, but it just doesn't seem to have the vibrancy of my other lenses where colour is concerned

Indeed you can spent hours on Boj's and when you look the next day you even find more new stuff, it's really large that site.

Most here already know it so the link was more directed to the OP but you're welcome

Btw do you know what a bird's-eye lens is, is it the same as a fish-eye?

Matt here is a list link

This is the sort of stuff that should be in our PUG wiki...