Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-30-2009, 05:45 PM   #1
Senior Member




Join Date: Oct 2009
Location: Florida
Photos: Albums
Posts: 231
Screw Mount

I picked up an old converter today that fit my K7, and has a screw mount. I'm trying to find an old film 50mm 1.4/1.8 because the kit lens isn't fast enough for what i want, and I'm spoiled by an old canon 50mm on my A1. I've noticed a few thread screw type lenses for Pentax around. Does anyone know if there is a specific thread type, or width I need to be concerned about? It seems that the focus may be off with this adapter setup. Would that also be true? Anybody shoot this setup?

What's the general knowledge with 50 mm (or 30, or 70) film lenses for Pentax Digital Cameras? Anything to avoid, or preferred?

Thanks...

12-30-2009, 07:19 PM   #2
Pentaxian




Join Date: Sep 2007
Location: Bay Village, Ohio USA
Posts: 1,025
QuoteOriginally posted by Snydly Quote
I picked up an old converter today that fit my K7, and has a screw mount. I'm trying to find an old film 50mm 1.4/1.8 because the kit lens isn't fast enough for what i want, and I'm spoiled by an old canon 50mm on my A1. I've noticed a few thread screw type lenses for Pentax around. Does anyone know if there is a specific thread type, or width I need to be concerned about? It seems that the focus may be off with this adapter setup. Would that also be true? Anybody shoot this setup?

What's the general knowledge with 50 mm (or 30, or 70) film lenses for Pentax Digital Cameras? Anything to avoid, or preferred?

Thanks...
If its a Pentax brand lens, either screw mount or bayonet, it will fit. The screwmount lenses will need your adapter, of course. Technically, the Pentax screwmount is referred to as an M42 mount. It is 42mm in diameter, with a pitch of 1 thread per mm. This is often referred to as a "universal" mount because, back in the sixties, there were many camera brands that used this thread.

Speaking of adapters, what type is yours? There are two types; the genuine Pentax adapter and its clones, and a cheaper type with a wide flange. The genuine Pentax adapter fits entirely inside the k-mount opening of the camera. The type with the wide flange does not; the flange is outside the opening and sits between the camera and the lens. This prevents focusing to infinity. This is fine, if you only intend to use the lens for closeup or macro work, but it is no good for general photography, where infinity focus is often needed.

If you buy a non-Pentax screwmount lens, try to get one with an Auto/Manual switch. All Pentax lenses have this. In auto mode, the lens remains wide open until the camera pushes the little pin in the lens mount, to close the aperture down to the working aperture. In manual mode, the lens responds as you turn the aperture ring, closing the iris down immediately. Since Pentax dslrs do not have the mechanism to push that pin, if you don't have the Auto/Manual switch, you can only use it wide open.

The Super Takumar 50mm, f/1.4 and 55mm, f/1.8 lenses show up on ebay quite frequently. The 50mm usually sells for $50 or less, and the 55mm for $25. Watch for a while to get a feel for availability and price.
12-30-2009, 07:35 PM   #3
Junior Member




Join Date: Jan 2009
Location: SE Connecticut
Posts: 38
Screw Mount Lenses

The best use for the M42 adapters is not for lenses, but for your old close-up bellows. Use with the M42 lenses in a PITA as you are still basically full manual mode - it's like a step backwards. You can make them work, but it's a hassle.
My favorite lens from the M42 days is the 50/1.4 - I still have two of them. I particularly like the feel of the SMC Takumar with the rubberized focus ring. But it was just too much bother on the digital SLR.
So, I bought another 50/1.4 - this one the K-mount A series. This gives me full aperture coupling with the digital SLR. And I kinda like the manual focus - gives me a little time to think about the shot. With the autofocus lenses, it's just aim & shoot (usually in that order).
12-30-2009, 08:36 PM   #4
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
Have a look at this thread as well.

12-30-2009, 08:39 PM   #5
Senior Member




Join Date: Oct 2009
Location: Florida
Photos: Albums
Posts: 231
Original Poster
Wow, this is more complicated than I thought. My SLR was simple.

Noblepa, I believe I got a non-flush one. It said Pentax on the packaging, but that could be misleading. It's nice, aluminum I believe, black anodized (maybe paint), fit well, but like you said, I don't want to be limited on use. I'll just take it back and order a flush type from Pentax.

I want to be as knowledgeable as you guys on this stuff. Takes time. I'm old fashioned and believe old lenses are better quality (not always, I know).

How about the FF film lenses with k7 and k-x? I realize the light circle is larger, but that seems like a good thing, right? I found an old (new) Promaster 100-300 and took a couple shots at a camera store, and the images were smooth. Max aperture is f5, but for daylight it may be ok.

Hey aesch, sorry for my ignorance, I'm new here, but what is PITA? I know I'll feel stupid when you tell me, and I'll act like I already knew and just forgot for a minute...

Thanks again...
12-30-2009, 10:39 PM   #6
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,166
QuoteOriginally posted by aesch Quote
The best use for the M42 adapters is not for lenses, but for your old close-up bellows. Use with the M42 lenses in a PITA as you are still basically full manual mode - it's like a step backwards. You can make them work, but it's a hassle.
My favorite lens from the M42 days is the 50/1.4 - I still have two of them. I particularly like the feel of the SMC Takumar with the rubberized focus ring. But it was just too much bother on the digital SLR.
So, I bought another 50/1.4 - this one the K-mount A series. This gives me full aperture coupling with the digital SLR. And I kinda like the manual focus - gives me a little time to think about the shot. With the autofocus lenses, it's just aim & shoot (usually in that order).
That's a very misleading post regarding adapters and the use of m42 lenses on dSLR. I suggest the OP take a look at this thread. Snydly will then re-assess this post. For example, Make Cash shoots extensively with Takumars and a K20d. Several of us on here use various vintage Takumars and other m42 lenses on or dSLR bodies.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/31601-takumar-club.html
12-31-2009, 02:44 AM   #7
Veteran Member
Mechan1k's Avatar

Join Date: Jun 2007
Location: Sydney, Australia
Posts: 2,883
The takumar club thread is literaly the bible when it comes to everything Tak ... and Mike Cash would be a Prophet ... hee hee.

Snydly ... do you have a pic of the adaptor you have ... or a pic with it fitted to your K7???

As for 50mm lenses available ... there are many ... the 50 f/1.4 is excellent ... also the the kit lens that was used back in the day 55mm f/1.8 is a little gem on a lens.

Like many here I a Tak convert and LOVE using them ... i hardly get the time though ... but have cracked the kit out tonight while at work ... and I am in love again.
12-31-2009, 07:45 AM   #8
Pentaxian




Join Date: Sep 2007
Location: Bay Village, Ohio USA
Posts: 1,025
M42 adapters

QuoteOriginally posted by Snydly Quote
Wow, this is more complicated than I thought. My SLR was simple.

Noblepa, I believe I got a non-flush one. It said Pentax on the packaging, but that could be misleading. It's nice, aluminum I believe, black anodized (maybe paint), fit well, but like you said, I don't want to be limited on use. I'll just take it back and order a flush type from Pentax....
Here's a link to an ebay auction for a Pentax-style adapter that fits flush:

Pentax K-Mount to M42 Thread Mount Adapter - eBay (item 390136004814 end time Jan-02-10 18:51:36 PST)

Here's a link to one with the wide flange:

M42 Lens Adapter Ring for Pentax K mount K200D/K110D - eBay (item 180424724808 end time Jan-23-10 23:59:46 PST)

If your adapter looks like the first link, then you're probably okay. Some people swear that that the genuine Pentax adapter is machined better than even the clones that look the same. I have a third party adapter and it works fine.

Many people, myself included, remove the metal spring clip from the adapter. This clip is intended to lock the adapter in place. It does that, but makes it more difficult to remove the adapter. You must first unscrew the lens from the adapter and then remove the adapter from the camera. With the clip removed from mine, I can simply treat my 50mm, f/1.4 Super Takumar as if it were a k-mount lens. I leave the adapter on the lens, since its the only M42 lens I use on my K10D. I've never had any problem with it being too loose and falling off. Friction is more than enough to keep the lens firmly in place.

12-31-2009, 08:25 AM   #9
Veteran Member




Join Date: Nov 2007
Location: In the present
Photos: Gallery
Posts: 1,870
QuoteOriginally posted by noblepa Quote
Since Pentax dslrs do not have the mechanism to push that pin, if you don't have the Auto/Manual switch, you can only use it wide open.
Incorrect. The most I would agree with is that you will have to (want to?) focus wide open, and even there I am not sure I agree. For me sometime focusing a stop or two closed gives a better result, a little finer focus if you will. But that is a fine point.

The manual/auto switch is not the key to using all apertures. I may be somehow missing what you are saying here, but I do not think so. Stripping the workflow down it is simply:

1. Open aperture fully (or not)
2. focus
3. set aperture to desired setting
4. meter (stop down with K10D/K20D)
5 shoot

No auto/manual switch required. Also probably less steps than you might use. i am guessing you do this:

1. set aperture
2. meter
3. open aperture (using auto/Manual switch if present)
4. focus
5. reset aperture (using auto/manual switch if present)
6. shoot

I prefer the first as it makes the most sense, but I find myself doing both in different situations. Both are particularly easy when using a preset with the detent. In fact I much prefer the flexibility the presets give me and find the use of the auto/manual switch relatively annoying.

The way I learned to use an SLR was with a preset lens. The subtle difference was that you usually had a hand held meter and so did the following:

1. meter
2. set preset detent/shutter speed as desired
3. open preset slider to full open
4. focus
5. closed preset detent
6. shoot

When shooting a sequence where the light did not change, all that was required was to open the preset slider, refocus, recompose, set the slider back and shoot. Nothing stopping you from doing this with a DSLR.

I actually find using a hand held meter and setting the values in manual mode works quite nicely for me with a DSLR. If compensation is required, I already tend to know how to do so with speed or aperture and I have tended now towards adopting the latter technique when using presets. It is familiar and works nicely.

No auto/manual switch. Full use of lens apertures.

woof!

Last edited by woof; 12-31-2009 at 08:32 AM.
12-31-2009, 08:39 AM   #10
Veteran Member
Nesster's Avatar

Join Date: Oct 2006
Location: NJ USA
Photos: Gallery
Posts: 13,047
A slight correction there:

You do need some method by which to stop down the lens yourself. If the lens has an A/M switch, setting it to M achieves this. A preset lens also, by its nature, achieves this.

Without the A/M switch you essentially have two choices:
- modify the mount so the pin stays pushed in
- use an adapter that contains an inner flange to hold in the pin (one is available):
Manual Focus Lenses :: View topic - Pentax-k /m42 adapter with inner flange

Takumars are the safest bet, they either have the A/M or are preset.
Vivitar I find usually has the A/M switch... it is a good idea to check with the seller first.

Re. the work flow, there is another:

- set camera to Av, apply some + exposure compensation
- open lens to wherever you can focus it
- close the lens to wherever you want to shoot it
- shoot
- adjust exp comp as needed


Thanks for all the positive press on the Takumar thread, it's the best thread I've ever started, but can't really claim any sort of specialness, as I'm certain someone else would have started it. Takumars really are the gem of the whole Pentax experience, they are what sets Pentax apart from all others.
12-31-2009, 08:42 AM   #11
Veteran Member
Nesster's Avatar

Join Date: Oct 2006
Location: NJ USA
Photos: Gallery
Posts: 13,047
Re. specific recommendations:
the 55/1.8 and the 50/1.4 have deserved reputations... and often, you pay for this rep. Often cheaper to buy attached to a camera Both work beautifully on a digital camera, I wouldn't worry too much about the differences - between the two, or between Auto, Super, S-M-C, or SMC - and simply enjoy the one I get first.

The Takumar 35 f/3.5 is an amazing lens, only problem is the f/3.5 speed. Small, sharp, handy. The Takumar 28 f/3.5 is also quite good, for some reason I find Pentax 28's have less of the tone concentration of their other lenses, but these are honest and sharp lenses.

These are all commonly available, so if you can contain the inevitable eagerness, often good samples can be had for under market prices.

A final point about screw mount: there are so many lenses available at such rock bottom prices, the opportunity to educate self about lens parameters and performance is cheap, fun, and quick. You can easily pick up a few 35's from different makes and see what YOU like about each.
12-31-2009, 08:47 AM   #12
Veteran Member




Join Date: Nov 2007
Location: In the present
Photos: Gallery
Posts: 1,870
QuoteOriginally posted by Nesster Quote
Re. specific recommendations:
the 55/1.8 and the 50/1.4 have deserved reputations... and often, you pay for this rep. Often cheaper to buy attached to a camera Both work beautifully on a digital camera, I wouldn't worry too much about the differences - between the two, or between Auto, Super, S-M-C, or SMC - and simply enjoy the one I get first.

The Takumar 35 f/3.5 is an amazing lens, only problem is the f/3.5 speed. Small, sharp, handy. The Takumar 28 f/3.5 is also quite good, for some reason I find Pentax 28's have less of the tone concentration of their other lenses, but these are honest and sharp lenses.

These are all commonly available, so if you can contain the inevitable eagerness, often good samples can be had for under market prices.
+1 on these recommendations.
12-31-2009, 08:51 AM   #13
Moderator
Site Supporter
Blue's Avatar

Join Date: Jun 2008
Location: Florida Hill Country
Photos: Gallery | Albums
Posts: 17,166
Another aspect about takumars is there compact size relative to their focal length. Compare a 35mm f3.5 Super Tak or S-M-C version to another brand. They are the inspiration for the Limited lenses. The only 35mm lens more compact is the Auto-Tak 35mm f3.5.
12-31-2009, 09:04 AM   #14
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by Snydly Quote
Wow, this is more complicated than I thought. My SLR was simple.
Basically it is NOT complicated:
– You can use all lenses with K-bayonett, but be careful with lenses with the Ricoh-KR-mount. It is has a little modification, compared to the original Pentax K-mount, that can lead to lenses getting stuck on a Pentax DSLR.

– You can use any M42 screw-mount lens. There are zillions available, using the Pentax M42/PK-adaptor. This adaptor mounts INSIDE the camera bayonett and no part of it sticks out! This asures infinity focus, as M42 and the K-mount have exactly the same sensor-mount flange distance.

Adaptors with a flange will make infinity focus impossible, but could be used with dedicated macro equipment, like bellows or extension tubes.

That is the general picture. Some specific features of the camera (P-TTL flash control, Program mode, Matrix metering etc.) can be used or not, depending on the lens capabilities.

QuoteOriginally posted by Snydly Quote
Noblepa, I believe I got a non-flush one. It said Pentax on the packaging, but that could be misleading. It's nice, aluminum I believe, black anodized (maybe paint), fit well, but like you said, I don't want to be limited on use. I'll just take it back and order a flush type from Pentax.
You could use that adaptor to mount an old M42 bellows, if you are pursueing macro photography, as aesch suggested

QuoteOriginally posted by Snydly Quote
I want to be as knowledgeable as you guys on this stuff. Takes time. I'm old fashioned and believe old lenses are better quality (not always, I know).
There is some nice glass available in older K or KA mounts or in M42. Even if it is not as good as modern glass, it might be an economic alternative, especially, if you use special lenses only rarely. But don't overestimate old glass as a rule. I personally think, that quite a few of old lenses are realy worth having, but most (out of many thousands) are obsolete, especially zoom lenses from the M42 era. Old telephoto lenses will almost always show visible to severe colour aberration, as these increase with focal length. Modern lenses always sport ED glass to correct these aberrations.

QuoteOriginally posted by Snydly Quote
How about the FF film lenses with k7 and k-x? I realize the light circle is larger, but that seems like a good thing, right? I found an old (new) Promaster 100-300 and took a couple shots at a camera store, and the images were smooth. Max aperture is f5, but for daylight it may be ok.
Especially cheapo lenses, like the Promasters deliver poorly on a DSLR - you want to have higher quality for digital. On the other hand max. aperture is not quite as important as in film days, as image stabilization has come a long way and is quzite useful, giving you between 1 and 2 shutter speed steps more latitude for handholding. Also, you'll find, that current Pentax DSLRs are very useable at higher ISO settings, which saves the day with slow lenses.

Generally FF lenses can be used to advantage with Pentax DSLRs, often getting rid of their poor corner performance.

Ben

Last edited by Ben_Edict; 01-01-2010 at 08:38 AM.
12-31-2009, 11:11 AM   #15
Pentaxian
reeftool's Avatar

Join Date: Dec 2007
Location: Upstate New York
Photos: Gallery | Albums
Posts: 8,009
As Ben mentioned, it really isn't complicated. With Takumars, I install the adapter and screw the lens in and shoot pretty much like I did with my Spotmatic. You just need to move the auto/man switch to the manual position as the DSLR won't work the aperture. Switching the lens back to auto opens up the aperture and keeps it there. I generally will leave the lens in manual but when the light is low I flip the switch to auto to focus with the lens wide open and back to manual to take the shot. My SP1000 has a switch on the body you have to move to meter so it's still a 2 step process, you just use the switch on the lens with the DSLR.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
50mm, film, k-mount, lenses, mount, pentax, pentax lens, screw, setup, slr lens, thread, type
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hey new here, quick question, is this K mount or M42 Screw Mount? Lulerfly Pentax SLR Lens Discussion 8 11-02-2010 11:58 PM
K-Mount to Screw Mount Adapter Ring is Stuck steve101a Pentax SLR Lens Discussion 27 03-24-2010 02:59 AM
For Sale - Sold: FA: Original PENTAX Screw Mount to K Mount Adapter M42 HogRider Sold Items 0 10-21-2007 02:12 PM



All times are GMT -7. The time now is 11:12 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top