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-   -   [Recovered Thread: 99053] (https://forums.steves-digicams.com/pentax-samsung-dslr-k-mount-mirrorless/96707-recovered-thread-99053-a.html)

ksm123 Jul 30, 2006 5:52 PM

Is it possible to use SLR Film camera lense in Digital SLR. Thanks in advance.

TDN Jul 30, 2006 6:04 PM

Yes it is. With Pentax you're probably even at the best adress for that.
Even with really old lenses without any electronic coupling you can use the metering in your camera.
Of course things like automatic aperture, autofocus, etc are up to the lens.

If you're interested in buying older lenses I'd suggest you look for KA mount lenses. They'll give you everything except autofocus.

All AF lenses work on the digital SLR of course.

TDN

Jul 30, 2006 6:12 PM

yes, there are only 24-27,000,000 of them out there..

ksm123 Jul 30, 2006 6:32 PM

Thanks for the reply.

Jul 30, 2006 6:36 PM

altho all of them work, there are some limitations due to design.

bilybianca Jul 31, 2006 1:40 AM

Any Pentax lens will work just as it did when it was produced. KA lenses give you automatic aperture, but no autofocus, just as they did when they were new. K lenses give you manual aperture and manual focus just as when they were new and autofocus only was a dream in some engineers mind. The optical and mechanical quality of older lenses are often first class, and you find them at bargain price on ebay and sometimes in the local fleemarket.

This is true only for Pentax of course (and Sigma, Tamron etc third party lenses with Pentax fitting). Be ware of N*k*n or C*n*n, as their older lenses are not compatible!

Kjell

NonEntity1 Jul 31, 2006 10:44 AM

I hope it is OK to ask a follow up question in this thread. If KA is the type of manual lens with automatic aperture (and the type to look for) and K does not, what other types are there? I think I have seen reference to K(M) and screwmount on some of the lenses I have seen on sale but these may be synomous terms for one of the types already mentioned.

Thank you,

NonEntity

bilybianca Jul 31, 2006 11:28 AM

K (M) probably means K (manual) if it's a Pentax fit lens. Screwmount is older, but non the less it can also be used on the Pentax DSLR's with an adaptor. But I'd recommend you to stick to the A versions if you don't have some experience with older cameras and shooting fully manual.

Kjell
Edit: Yes, A or KA (same thing) is exactly what you say.

The Barbarian Jul 31, 2006 12:12 PM

It should also be noted that with a screwmount-to-Kmouint adapter, even the old screwmount Pentax lenses can be used.

I am very pleased with the results I get from my 1.8 85mm screwmount Takumar.

Everything is manual, of course.





TDN Jul 31, 2006 3:14 PM

Be aware of anything that mentions "Ricoh" though...these lenses can get stuck on your camera.

You can recognize them by the name R/-KA P/-AR or something of that fashion.

TDN

NonEntity1 Aug 1, 2006 7:35 AM

Thank you.

themacguy Aug 1, 2006 5:28 PM

So how does one actually meter with a KA lens? Set it to the "A" position? (I'm guessing)

And haw about if one had a "K" mount that didn't have the AE function? I would imagine that you'd set the shutter speed on the camera and then rotate the aperture ring until...something...displays in the viewfinder? What might that something be?

Third question: If you have the "standard" zoom lens that accompanies this camera body, how does one adjust the aperture? (And is there a means for metering to occur other than "stopped-down" or just reading the display and setting things manually?)

Obviously, I have no experience with a DSLR although I did own a number of Minolta SRT 35mm SLRs in the 70's. I'm a big fan of the "match up the needles and shoot" school.

Any info, opinions, comments are welcome!

Thanks,
Barry

TDN wrote:
Quote:

Yes it is. With Pentax you're probably even at the best adress for that.
Even with really old lenses without any electronic coupling you can use the metering in your camera.
Of course things like automatic aperture, autofocus, etc are up to the lens.

If you're interested in buying older lenses I'd suggest you look for KA mount lenses. They'll give you everything except autofocus.

All AF lenses work on the digital SLR of course.

TDN

TDN Aug 1, 2006 6:04 PM

Yes, your lens need to be set on the "A" position on the aperture ring.

A KA lens will give you everything the kit lens has, except the autofocus.

This means you can use it in all modes on your camera, including Program, Aperture priority, Shutter Priority and of course Manual.

What I mostly do is set it to Shutter Priority, and let the camera decide on the aperture.

With older lenses it depends. I've heard that some lenses require "stop down metering", I'm not sure which ones though. I'm sure someone else with more experience will jump on this soon :)

TDN

themacguy Aug 1, 2006 8:45 PM

TDN,

Thanks very much for your comments. I'm getting the picture (no pun intended).

mtngal Aug 1, 2006 10:33 PM

I often use K lenses (well, M lenses, but they are essentially the same thing). If you use anything other than M mode on the camera, the camera will shoot with the lens wide open - it won't stop it down at all (not a problem if you were planning on using that aperture anyway). Otherwise, you set the camera to "M", then set the desired aperture on the lens ring. There's a button on the back that is the AE-L, you push that to temporarily stop down the lens so the camera can meter - you don't have to set the shutter speed at all (you can if you want, just don't press the button). Focus and shoot (I tend to focus first, then meter - don't think it makes a difference).

themacguy Aug 1, 2006 11:05 PM

I'm not sure I understand the part about "you can if you want, just don't press the button". Which button?

mtngal wrote:
Quote:

I often use K lenses (well, M lenses, but they are essentially the same thing). If you use anything other than M mode on the camera, the camera will shoot with the lens wide open - it won't stop it down at all (not a problem if you were planning on using that aperture anyway). Otherwise, you set the camera to "M", then set the desired aperture on the lens ring. There's a button on the back that is the AE-L, you push that to temporarily stop down the lens so the camera can meter - you don't have to set the shutter speed at all (you can if you want, just don't press the button). Focus and shoot (I tend to focus first, then meter - don't think it makes a difference).

Peacekeeper Aug 2, 2006 2:30 AM

What he is saying is that you can manually set shutter and aperture using M Mode setting. Manually set aperture ring and then move the thumb wheel to adjust the shutter speed.

Or

Set to M mode, then set aperture ring on the lens (as above), to automatically set the shutter speed to the right setting for the correct esposure (instread of manually turnig the thumb wheel), hit the AE-L button which is marked AE-L to the right of the thumb wheel.

This will cause the camera check the available light and make the appropriate adjustment to the shutter speed.

What he was saying by "Don't hit the button" is if you want to manually set the shutter, dont hit the AE-L button.

Crash

TDN Aug 2, 2006 4:45 AM

Oooh, I didn't know that. I thought that using K lenses forced you to use all manual settings.

So basicly pressing the AE-L button while in M mode gives you soem sort of aperture priority setting?

cool, I'll remember that when using my macro extensions:)

TDN

ejbrusselsprout Aug 2, 2006 6:56 AM

yes,

i use the ae button as described whenever i use my ext. tubes because they're the "auto" ones which means all manual except they allow focussing and composing with the ap. wide open, then stop down for the shot. with those tubes behind an a or fa type lens (like my sigma 70-300 macro) and the camera on manual the ae button is essentially ap priority and you can still adjust the shutter with the thumb wheel which is like exp. compensation if you want to think of it that way.

i find i often (maybe should say usually) have to bump the shutter as much as a stop or two slower to get a proper exp. using the tubes. can't say i've used manual much with just the lens so don't know if it's the tubes or the meter. it's not much of a problem as i work slow and review (with the histogram) fairly frequently.

if it hasn't been mentioned remember if you're going manual with alens that has an aperture ring you have to set the camera to "allow aperture ring" as the default is to not allow. puzzled why pentax didn't just make the default to allow.

all the best, eric

themacguy Aug 2, 2006 10:25 AM

Many thanks to those who are replying to this thread. I now have a much better understanding of how this all works.

:cool:

Monza76 Aug 4, 2006 8:46 AM

BTW one quick recommendation, buy Pentax. Pentax and Takumar lenses were built specifically for Pentax cameras and, as such, do not suffer from some of the problems associated with non-Pentax lenses (such as the built-for-Ricoh stuck lens issue). In early AF lenses it is an issue of electronic compatability, some third party lenses do not communicate properly with the camera sometimes resulting in very minor exposure problems. A, F and FA Pentax are the best choices. Even my Takumar-F zoom (a real cheapie) gives excellent results.

I have found an old Sigma AF 28-80mm that worked on the MZ-7 but would not auto focus on the DL (have no idea why but suspect it is an issue with electronic communication). And I find that my FA and DA lenses consistently produce better exposures than my new Sigma (the Sigma will underexpose). Maybe this is a fluke with my lens (it is the troublesome 24-135mm that many people had to return, mine does work well). If you look at the EXIF data for these third party lenses you will find that they identify themselves as some Pentax lens or other, my 24-135mm f2.8-4.5 Sigma tells the camera that it is a Pentax-F 28-80mm f3.5-4.5!! Interesting when you then read the shot was at 135mm (that still records properly).

I hope to start collecting some interesting Pentax A-series lenses when I can afford it.

Ira

DigitalAddict Aug 4, 2006 9:17 AM

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This info is exactly what I need.

Yesterday I stopped by at a pawn shop and got myself a KS Super Sears body (Ricoh)
with the lens mentioned above (Ricoh) AND Pentax SMC-M 50mm/F2 for $50.
(good I did not try the Ricoh lens on the body).

Pretty exciting. Can any of you point me to that guy's web site with the history of Pentax lens, often mentioned in forums?

P.S. I am a digital SLR newbie coming from C*n*n film SLR. Good I am able to reuse
the remote controller:-)



Monza76 Aug 4, 2006 9:37 AM

DigitalAddict, check out the Ricoh lens, if it does not have a P setting on the aperture ring it may be compatable with your camera (check and see if the entire mount area is exactly like the Pentax-M). I have two old Rikenon XR lenses that work fine because they are first generation Ricoh K-mount, before they started to do their own thing with the mount.

Ira

BTW I want your camera!


bilybianca Aug 4, 2006 2:25 PM

DigitalAddict wrote:
Quote:

Can any of you point me to that guy's web site with the history of Pentax lens, often mentioned in forums?


http://www.bdimitrov.de/kmp/

also have a look at this:

http://stans-photography.info/

Kjell

DigitalAddict Aug 4, 2006 2:41 PM

Apreciated.

I will probably make an extensive list with the lenses so I have it handy when going to a pawn shop next time (those to avoid as well).

Boy, I never thought it will come to this, LBA that is :-). It is all your fault.

I spent the last 3-4 months reading this and other Pentax forums before deciding on K100D. I need a vacation:-)




bilybianca Aug 4, 2006 2:51 PM

DigitalAddict wrote:
Quote:

I need a vacation:-)
Don't forget to bring your camera... and the lens list, who knows what you might bump into...;)

Kjell

Monza76 Aug 4, 2006 4:18 PM

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This image probably won't look good here, but you should see it full size. This was shot with the 50mm f1.7 M lens at f1.7, the DOF is miniscule but the exact centre of the frame is in sharp focus, honestly.

Ira

DigitalAddict Aug 4, 2006 4:33 PM

Being a newbie I am yet to discover opportunities where a faster than F2.8 setting will be desirable for a non-macro lens (not sure about macro either).

Can you share some from your experience?



TDN Aug 4, 2006 4:45 PM

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DigitalAddict wrote:
Quote:

Being a newbie I am yet to discover opportunities where a faster than F2.8 setting will be desirable for a non-macro lens (not sure about macro either).

Can you share some from your experience?


concerts!
At a concert every fstop you can get is one you can use...

I'm saving up for a good concert lens, because with my current equipment I'm a little short. My ratio of useable images at a concert drops down to about 1 out of 10, while I'm usually able to get a good 1 out of 3 in other situations.

It's a hard, but also a fun branch of photography, once you get into it.

check here to see what I mean:
http://www.tdn9.be/photo.php?id=17
http://www.tdn9.be/photo.php?id=20

From that first one I had an awesome shot, yet it was unuseable because a too slow shutter speed and out of focus-blur. If I had had a 1.4 or 1.7 lens in that case, it would have been the shot of the year:p (see attached img)

TDN

mtngal Aug 4, 2006 5:05 PM

I was indoors and trying to take pictures of trophies behind glass. I was using a polarizer to cut down on the glare, and the 1.7 lens I was using allowed me to keep the shutter speed fast enough to avoid camera shake.

Peacekeeper Aug 5, 2006 1:11 AM

1 Attachment(s)
For non-macro application the aperture settings of f/1.7 and f/2.8 are great if you are chasing short DOF. This allows you to isolate your subject from the crowd or from a busy background.

The subject become aparent in the photograph,as per this example.

300mm at f/4. ISO 400 1/320sec.



TDN Aug 5, 2006 8:24 AM

oh cool, I didn't know that.

There, another piece of wisdom gathered :) Thanks crash!

TDN

bilybianca Aug 5, 2006 9:05 AM

1 Attachment(s)
DigitalAddict wrote:
Quote:

Being a newbie I am yet to discover opportunities where a faster than F2.8 setting will be desirable for a non-macro lens (not sure about macro either).

Can you share some from your experience?



Large aperture (low f-number) = shallow/thin depth-of-field (sharpness from-to, counted in distance from camera).

Small aperture (high f-number) deep depth-of-field

Im macro, DOF gets so thin that it is usually uninteresting to use large apertures if you don't try to achieve a special effect. Therefore fast macro-lenses are not normally that desirable, you will seldom use the large apertures anyway.

Fast non-macro lenses allows you to do two things. First the thin DOF on purpose as demonstrated sowell and nicely by Crashman in the post above. Secondly it may allow you to take a photo hand-held in low-light conditions where a slower lens would have left you with nothing or just some motion-blurred coloured fields.

This was taken with my 50 mm FA 1.4 @f1.4, 1/20 sec, ISO400. No flash. No artistic masterpiece, but it demonstrates what a fast lens can do for you.

Kjell

DigitalAddict Aug 5, 2006 11:05 PM

Clearly I have plenty to learn on the subject.Thanks for advice guys.

Nothing beats real life examples. It seems to me, the newbie, that the focal distance plays a role as well in getting the right DOF. Or not?

Would the sameDOF be possible on a 50mm vs 300mm with the same F4 aperture?

Hope not to bore you to death with my questions...

Peacekeeper Aug 6, 2006 1:02 AM

1 Attachment(s)
No such thing as boring anyone here with questions about photography.

There is a ratio of DOF to the focal distance from camera to subject and the f stop.

I have seen a chart somewhere that points out how long the DOF is at certain focal distances.

Obviously at short focal distances the DOF is almost a sliver of focus. Thats why macro photography is so difficult. You have to shoot at small apertute to try and get the longest DOF and by doing that you have to drop your shutter speed right down.

Something to do with the 'rule of thirds' and I don't mean the composition rule. The DOF extends 1/3 in front of your point of focus and 2/3 beyond. So if your DOF is about 3 metres, when you focus on your subject then 1 metre in front will be in focus through to 2 metres beyond your subject. If you were to walk closer to your subject and re-focus then the DOF will reduce in depth.

The example below demonstrates how a simple change in F stop can increase your DOF.

Both shot at 70mm at 200 ISO. The left side is f/2.8 at 1/1000, the right side is f8 at 1/160.

You can see the left side DOF starts at the second sailor in and extends through past the officer but not to the second group of sailors. The right side image at f8 has a longer DOF and starts at the first sailor and extends pretty much to infinity (well not really but you would be hard pressed to see where it stops.) Look at the banners on the poles to see that they are in focus.

So opening up your aperture will shorten your DOF, being close to your subject will shorten your DOF as well. Longer focal lengths aparently also can have an impact.

If you want long DOF keep your shutter speeds down and your aperture closed to at least f8 and use longer lens to put some distance between your camera and your subject.

Crash

edit..

This is a cut and paste from http://en.wikipedia.org/wiki/Depth_of_field

Thus for a given film format, depth of field is calculated from three factors: the focal length of the lens, the f-number of the lens opening (the aperture), and the camera-to-subject distance. While it is commonly said that lenses of short focal length have greater depth of field than long lenses, this rule of thumb is not strictly true because it takes into account only one of the three factors. In fact, for a given subject framing and aperture, lenses of all focal lengths have approximately the same depth of field. This is because subject framing is dependent on two of the factors (focal length and subject distance), while aperture is the third. Once the three factors are set in a fixed proportion, the depth of field will be almost the same.

An example makes this easier to understand. Take a photographer using a 400 mm lens to shoot a subject (for example, a bird) 10 metres away. Assuming an aperture of f/2.8, the depth of field of this shot would be 10 cm. Should the photographer now switch to a 50 mm f/2.8 lens, the depth of field at 10 metres is now 7.62 metres. However, once the photographer has moved to 1.25 metres from the bird, being the distance required such that the bird fills as much of the frame as it did with the 400 mm lens at 10 metres, the depth of field is almost exactly the same as before, 10 cm. In some cases, though, the DOF of one lens may extend to infinity, or nearly so, and the other still finite, so the approximation can break down in such cases.




Peacekeeper Aug 6, 2006 1:27 AM

You got me looking now.

An online DOF calculator

http://www.shuttercity.com/DOF.cfm

Examples and tutorials

http://www.photozone.de/4Technique/compose/seperate.htm

http://www.photozone.de/4Technique/compose/dof.htm

http://www.luminous-landscape.com/tutorials/dof2.shtml



bilybianca Aug 6, 2006 6:56 PM

Thanks Crashman for those links, they are really worth a look for those of you who haven't already done so.

Kjell

bper Aug 6, 2006 7:05 PM

I don't know if any of you have reason to need information on the old screw mount lenses, but I ran across this site when I was researching a 50mm F4 macro SMC Takumar - Bruce

http://www.aplimited.com/pentax/pages/home.htm

Monza76 Aug 6, 2006 11:23 PM

Since we have drifted into prime fast lenses in this thread let me point out something else that separates digicams from dSLRs, actual focal length.
- Most of us do not own lenses with focal lengths less than 18mm, this gives the equivalent of 27mm on a 35mm film camera because of the size of the digital sensor (APS vs 35mm, result 1.5X crop factor).
- The typical zoom digicam with a 1/2.7 sensor has a sensor so small that the crop factor is about 6X, this means that a 6mm lens results in the equivalent of about 36mm in 35mm film format. As a result a small digicam (I have a Fuji 2800Z in front of me as I type) may have an equivalent to 35-200mm but its actual focal length is 6-36mm.
- The shorter the focal length a lens has, the greater the DOF at the same marked aperture.
- Result of all the information above, digicams have tremendous DOF. This means that it is difficult to separate a subject from its background unless you are very close to the subject and very far from the background (or vise versa). This is part of the reason why digicam users are often disappointed when they purchase their first dSLR, they get pictures that do not have the sharp focus of their digicam, because the dSLR lens has a greater focal length thus it has less DOF, it is more prone to pictures where some of the subject is out of focus. The picture I posted above is a good example, to most it will just look out of focus.

Controlling depth of field is one of the primary reasons for owning a dSLR, it is also the reason many very good photographers prefer Av mode over program. In Av mode they can have control over DOF. Tv mode is useful if you need to stop, or exaggerate, action but if your subject allows it, Av gives more control over the look of the final image.

Check out the budget bins at your local book store for books on 35mm photography, they are usually considered obsolete and sold cheap, but all of the information about lenses, composition, lightingand basic photographic terms still apply with digital and are very valuable. Anything you can't find, ask here and someone will answer.

Ira

Peacekeeper Aug 7, 2006 12:54 AM

Talk about revisiting my phtoography training from 26 years ago..well, there is nothing wrong with a good refresher of the ntus and bolts of how it all works, is there?

:O


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