Author Topic: Pentax lenses and adaptors (Read 2080 times)

oznasia · « **on:** June 03, 2011, 08:04:28 PM »

I am a relative newcomer to interchangeable-lens photography and a complete newcomer to using legacy lenses but I want to get started. I dropped into a shop selling used photo equipment and he had a Pentax f1.8 50mm macro lens (I didn't check the mount). I tried it on a Pentax camera that he had and I could focus well at about 1 inch and also at about 2 ft. He's asking around US$130 for it.

I haven't bought it yet. I'm asking advice so I make the right decision. I asked someone what adaptor they recommended. They suggested a Soligor auto extension tube set. I'm a bit lost here. Does that function as an adaptor? Or do I still need a separate one? This person told me to avoid the cheap Chinese adaptors as they create a halo effect.

I've looked on ebay. There are many adaptors for Pentax PK mount (still have to check if that's what it is). They range in price from about US$16.50 to 45. What do I have to pay to get a good one and what brands should I go for or avoid?

BTW, I trust it doesn't matter but I'm using a Panasonic G2.

Thanks, your advice is appreciated.

Em5 Pete · « **Reply #1 on:** June 03, 2011, 08:34:18 PM »

The Pentax PK is a bayonet mount, Pentax also had a Pentax M42 screw mount..

AS far as adapters... get the ones that are Brass and Aluminum... Cost: Depends... I have bought the $25.00 variety's for Nikon and Pentax M42. Both work fine. You may find that you hit INF and then go past it on the G2. Doesn't matter, you focus through the lens anyway, As long as it can get to INF, your fine.

Now a if want a better quality: they are around $85.00 BIN

Example
PK to m4/3 adapter Auction with BIN (NYC)

oznasia · « **Reply #2 on:** June 04, 2011, 06:03:51 AM »

Thanks for the advice and the pictures help. I went back to the shop today. The guy wasn't there but his wife was. She speaks very little English. I was wrong about the lens. It is f2.8. Is it PK? She seemed to be saying so but I'm still not certain. I can't find any such designation on the lens. By 'bayonet' do you mean that as you focus the lens moves in and out? Because that's what it does. Should have snapped it.

Are you also saying that I need the adaptor whether I buy the extender or not?

I'm happy to buy an adaptor in the middle of the price range but I need to find a dealer who will ship to Malaysia.

Em5 Pete · « **Reply #3 on:** June 04, 2011, 07:06:42 AM »

P or PK, Pentax Bayonet

M42, Pentax Screw

N or Ni, Nikon Bayonet

C or CA, Canon Bayonet

rparmar · « **Reply #4 on:** June 04, 2011, 09:29:35 AM »

Most of this has already been covered but maybe a summary will help.

Pentax make excellent lenses and have done so for ages. Originally these were in M42 mount, which is a screw fitting: the lens screws into the body over several turns. Then came the K-mount which is a bayonet: half a turn and the lens clicks into place. Following this was the KA mount which has connections for aperture coupling. There are many variations but they don't matter when connecting to MFT since none of the info is read and the lens will always act totally manually.

You can get K-mount to MFT and M42 to MFT depending on your needs. I have a cheap $20 eBay job. The pin does not hold every lens in place. This is the only deficiency I can find and it's not a deal-breaker so long as I do not accidentally unscrew the lens from the adapter!

I am writing a series of articles on just this. Check out Comparing Camera Size: Pentax K20D Versus Olympus E-P1.

rparmar · « **Reply #5 on:** June 04, 2011, 09:37:23 AM »

From oldest to newest, Pentax K-mount lenses have the following designations: K, M, A, F, FA. Except for the oldest these codes are found on the lens itself. But if the lens simply says "SMC" then it is a K generation (not to be confused with K-mount). All are good for MFT. In fact, the older the lens the cheaper as a rule. And IQ does not suffer.

Here are the 50mm macros by generation. This should make the nomenclature clear.

"SMC Pentax 50mm F4 Macro"
"SMC Pentax-M 50mm F4 Macro"
"SMC Pentax-A 50mm F2.8 Macro"
"SMC Pentax-F 50mm F2.8 Macro"
"SMC Pentax-FA 50mm F2.8 Macro"

So you are looking at the A, F or FA. US$130 is a good price for this excellent lens, one of the sharpest ever made. I believe it does 1:2 macro which is good for that focal length.

oznasia · « **Reply #6 on:** June 04, 2011, 04:51:25 PM »

@ Robin: a quick reaction. You seem to be suggesting that I can't go far wrong with this lens at this price. Perhaps I should simply buy the lens and then work out what it is and get the appropriate adaptor later.

rparmar · « **Reply #7 on:** June 04, 2011, 06:52:28 PM »

Yes, I'd say you are right. If you are at all interested in a macro lens at this focal length, and don't mind using manual mode, then it looks like you can't go wrong. It's either an A, F or FA lens, likely the first. It'll be very well made, a solid chunk of metal and glass. So long as it's in good shape now, it will be for years to come.

If you don't want macro you can get a 50/1.7 or 50/1.4 for less money. They aren't as incredibly sharp, but are very good.

oznasia · « **Reply #8 on:** June 04, 2011, 07:19:55 PM »

Thanks Robin. As for condition, it looks used and not so young but the glass looks good and using a Pentax camera it focuses well. I'll pick it up soon and post a pic of it.

oznasia · « **Reply #9 on:** June 04, 2011, 09:18:04 PM »

I'm just rereading all this to try to get some understanding. I'm assuming that K mount and PK mount are one and the same thing. Correct?

rparmar · « **Reply #10 on:** June 05, 2011, 06:03:18 AM »

Quote from: oznasia on June 04, 2011, 09:18:04 PM

I'm just rereading all this to try to get some understanding. I'm assuming that K mount and PK mount are one and the same thing. Correct?

Yes!

http://en.wikipedia.org/wiki/K-mount

oznasia · « **Reply #11 on:** June 05, 2011, 08:14:55 PM »

Thanks. The wikipedia page is very useful.

oznasia · « **Reply #12 on:** June 06, 2011, 02:37:56 AM »

Well, after all this, I returned to the store this afternoon and took a closer look at the lens. And I see that the letters that are almost scratched off read 'SIGMA'. Yes, it's a Pentax mount but not a Pentax lens. I'm wondering if it's still such a good buy.

voyager · « **Reply #13 on:** June 06, 2011, 02:57:54 AM »

Are you sure it's a 50mm f/1.8? Sigma doesn't have that lens.

watkins · « **Reply #14 on:** June 06, 2011, 03:48:19 AM »

Quote from: voyager on June 06, 2011, 02:57:54 AM

Are you sure it's a 50mm f/1.8? Sigma doesn't have that lens.

He's already said it's a 2.8, being sigma it's not worth as much...but I have no idea what it is worth,or how good it is so I'll leave that to the experts...

voyager · « **Reply #15 on:** June 06, 2011, 03:50:31 AM »

The Sigma 50mm f/2.8 Macro for $130? If I've got that right, then wow, that's an amazing deal!

oznasia · « **Reply #16 on:** June 06, 2011, 05:58:12 AM »

Thanks for the feedback. Everything I've been reading has been about Pentax and that's the lens that was originally recommended to me. You seem to be suggesting that the Sigma lens (yes 2.eight) would be a good buy. I can still buy it tomorrow. Where can I read more about this lens, particularly in relation to M4/3 if possible?

oznasia · « **Reply #17 on:** June 06, 2011, 06:29:01 AM »

Here's some pics of the lens:

rparmar · « **Reply #18 on:** June 06, 2011, 06:31:08 AM »

Quote from: oznasia on June 06, 2011, 02:37:56 AM

Well, after all this, I returned to the store this afternoon and took a closer look at the lens. And I see that the letters that are almost scratched off read 'SIGMA'. Yes, it's a Pentax mount but not a Pentax lens. I'm wondering if it's still such a good buy.

No. Leave it.

First, I am not a fan of Sigma build compared with Pentax. Secondly you can get this lens cheaper -- last one on eBay went for 50 pounds. Third, if it has the name scratched off it is in shoddy condition... who knows what else is wrong with it? And lastly, the Pentax lenses have better IQ.

Hold out for a Pentax A 50mm f/2.8 in very good to excellent condition.

rparmar · « **Reply #19 on:** June 06, 2011, 06:42:03 AM »

Clarification: last two sold on eBay for £57 and £66, that is $93 and $108.

Please note that from the picture this is not the recent model but an older one with only manual focus. That doesn't matter for use on MFT but does for resale value. This lens is both bigger and heavier than the equivalent Pentax model... two more strikes against.

If you are happy with the not-so-great quality of this specimen, then point out to the seller the condition and lack of auto-focus. Offer $75 and accept whatever you are happy with. Make sure you have a 30-day return guarantee so you can be sure it works properly.

But this is random advice without knowing your context. It really depends on how much disposable cash you have and how much you want a macro lens. If you are only interested in this lens because it happens to be on hand, I'd say forget it.

Em5 Pete · « **Reply #20 on:** June 06, 2011, 06:50:45 AM »

I concur, A Pentax Branded "A" 50mm f/2.8 Marco is a better choice.
(Means it Manual Focus, and has all the needed contacts for Full Auto exposure on newer body's) But, it is also the last batch of lenses before AF lenses where made.

Pentax has 2 designations on later made lenses... This letter will on the "Brand Ring" on the front of the lens.. IT IS NOT the letter on some aperture lock on the f/stop ring at or near f/16 or f/22

"M"= has contacts to allow Aperture Priority and Shutter Priority BUT NOT Program on body's that offer these simi-auto exposure modes,

"A" = has contacts to allow Aperture Priority and Shutter Priority AND Program on body's that offer these simi-auto exposure modes,

Not of importance on a m4/3 body, but something to know about. Some say the "A" series are better optics with some lenses.

Em5 Pete · « **Reply #21 on:** June 06, 2011, 06:56:43 AM »

BUT, for the same money, or less, A 55mm Micro Nikkor f/3.5 or f/2.8 is an excellent lens as a portrait and a macro,

I paid $65.00 for 3rd generation f/3.5 -non Ai -- that had been converted to work on Nikon's that used a small pin at 2pm pm on the lens mount, instead of the large wishbone coupler that Nikkor lenses are identified with.

oznasia · « **Reply #22 on:** June 06, 2011, 07:26:25 AM »

Thanks for the advice. I'll check again tomorrow to see if anyone has any strong disagreements with the most recent posts. Otherwise it looks like I'll let this one go.

Author Topic: Pentax lenses and adaptors (Read 2080 times)

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