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Krasnogorsk-3 Mount type change


Allen-Deon Saunders

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Question 1:

Is there a way to change the mount type on a K-3? I’m looking to change it to the bayonet mount without anything crazy needed. I am aware there are 3 party mount conversions but they are cheap and I don’t want something temporary or just plain weak. I’m asking because some of the K-3 where made with a bayonet mount but I recently just bought one with a m42. I’m looking to use ARRI Zeiss glass from the 70s on the K-3 with bayonet mounts. Just wondering if anyone has found a solution to converting the mount. I’m also looking for suggestions into mount conversions for modern lens mounts IF you know of them working yourself DIRECTLY. I have seen YouTube videos of some stuff but nothing decent enough that I’m convinced it is a good solution. 

 

Question 1 follow up:

If you have had a K-3 and used other lenses besides the stock zoom: Was the lens appropriately distanced from the film so that the focus was accurate?

Meaning: the focal point of the lens of your lens (m42 mount which wasn’t the stock lens) was correct such that the image produced from the lens was entire in focus without any modification to the body of the K-3. 

Please list your setup if you have used this camera with another m42 mount lens and it worked. 

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No direct usage with the following links. I rejected my newish K3 sometime ago as a reliable camera. It kept jamming with simple load tests. 

Some specialized M42/PL Mount adapters that may work in conjunction with an Arri Bayonet/PL Mount adapter. Careful. Only specific PL/Bayonet lens will work especially if the rear element protrudes deep into the adapter. You do not want to hear a spinning mirror crunch. 

As in Rolling Stones's "Shattered". 

https://www.rafcamera.com/m42-lens-to-arri-pl-mount-adapter

https://araxfoto.com/accessories/pl-m42_adapter/

 

Nicholas

 

 

 

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1 hour ago, Nicholas Kovats said:

No direct usage with the following links. I rejected my newish K3 sometime ago as a reliable camera. It kept jamming with simple load tests. 

the Krasnogorsk cameras are notorious of jamming if the sprocket roller is installed incorrectly or if it's shifted a little. It can be installed multiple ways but there tends to be only one position where it does not jam occasionally. If it was the roller issue then it can be corrected relatively easily by adjusting the roller position

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@Nicholas Kovats

 

i just realized you sent the wrong mount converter. Please re read my post again as you responded too fast. I’m looking to convert to bayonet FROM m42. I’m wondering if I can find a good conversion from someone that has ACTUALLY done it. Recommendations from people with no experience doing it doesn’t really help. Thanks though. 

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There is only one direction for this type of adapter as the M42 FFD is less than the Arri PL FFD, i.e. 

M42 FFD = 45.46 mm (camera mount) 
Arri PL FFD = 54 mm (lens mount)

Replacing the K3 M42 hard front with an Arri Bayonet is not trivial nor inexpensive. It would be less expensive to purchase a used Arri 16mm camera with an Arri Bayonet mount, i.e. 

https://en.wikipedia.org/wiki/Arri_bayonet
"...SB (only one turret), ST/B (only one turret), M/B, 16BL, Arriflex 16SR, and Arriflex 16SR2 (early models)."

Les Bosher might be able to assist you with your desired hard front, i.e. http://www.lesbosher.co.uk/ under his CAMERA CONVERSIONS tab. Good luck on finding another filmmaker who has undertaken this type of conversion.  

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  • 2 weeks later...

@Will Montgomery

Hey Will,

You are right Pentax Super Takumar lenses are great. Do you have experience with this camera (K-3)? I am asking because even though it has an M42 mount it is far more technical than that. The Flange Focal distance from the mount to the film is about an inch. Most 35 mm cameras with a m42 mount type have a different distances for the image to be in focus (flange focal distance). Meaning, Unless someone has actual used a still lens on this camera, developed film, and then seen the results I cannot assume that option works. Do you have experience shooting with still lenses on this camera?

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13 hours ago, Allen-Deon Saunders said:

Most 35 mm cameras with a m42 mount type have a different distances for the image to be in focus (flange focal distance)

No, they don't. The M42 FFD is 45.46mm, as Nicholas said, whatever the camera. Any M42 lens will focus properly on an M42-mount K3, assuming it is correctly adjusted.

13 hours ago, Allen-Deon Saunders said:

Unless someone has actual used a still lens on this camera, developed film, and then seen the results I cannot assume that option works. Do you have experience shooting with still lenses on this camera?

You don't need "experience" and you don't need to "assume". It's a fact.

 

 

13 hours ago, Allen-Deon Saunders said:

The Flange Focal distance from the mount to the film is about an inch

No, it isn't.  Just get a ruler and measure it yourself. I've just done it- it's just short of 2". That's because it's 45.46mm- see above.

 

FYI, the contributors on this thread know what they're talking about- it's a professional forum

Edited by Mark Dunn
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@Mark Dunn

 

If you took physics and read manuals you would know two things: the formulas I posted as a picture in the reply and that each lens has a FFD. Have you ever wondered why mount converters have different depths ? It’s because different lenses have different FFDs and the design is a compensation for the difference in FFDs. Duh. In fact if you think I’m joking or being rude like you are you should take an optics class and talk with me about it after. Think about what you type after you see this reply. Don’t assume I’m dumb. 

83563DDD-706F-468D-8150-A064B824D4E9.jpeg

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Allen-Deon, Mark is right that any lens with an M42 mount will be set up to focus correctly on an M42 mount camera. Sometimes a lens may need adjustment because of wear or tampering, but generally the setting remains intact.

Your drawing of a simple lens describes how different focal lengths will have different back-focus distances, and although in practice a lens is much more complicated than a single glass element, you are correct that each lens will have its own distance from rear element surface to film plane. However, each lens is then housed with a lens mount that seats the lens at the appropriate distance. As long as the lens mount matches the camera mount, the lens should focus correctly. If you look at different focal length lenses with the same mount, you will notice the rear elements sit at different distances relative to the mount seat, but if it's an M42 mount for example, each lens will be situated to focus correctly when mounted to a camera with the M42 mount and flange depth of 45.46mm. 

Adapters are needed to adjust between different mounts and their different flange depths.

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@Dom Jaeger

 

the listed FFD for the lens which comes with the K3 is different than what is listed for the Pentax Lenses. By about 5mm. What you are saying may be true for SLRs but .... physics is physics and these are optics. Had I not done the research what you are saying would be true but the documentation speaks for itself. I’m not making this up out of thin air I promise you. This is why I posted it on the forum in the first place. Simply because I had thought about it so much that I needed a second opinion. If you don’t believe me find a lenses with an m42 Mount (for SLRs) check the FFD then check the FFD for the Russian camera. Sometimes things aren’t as cut and dry as we read them on the internet. The FFDs are different. I was posting to see if anyone has had luck with mount changing. I wasn’t trying to prove something as simple as fact checking FFDs of different lens between SLRs and Cinema cameras. I apologize for my long winded response but these are the physical facts. 

Edited by Allen-Deon Saunders
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Have you actually tried an M42 Pentax lens on your K3 to see if it works? You can judge if the focus marks line up through the reflex viewfinder. You could also measure the K3 FFD roughly yourself with say a wooden cotton bud stem and the mirror out of the way.

Where are you getting your information about the different FFDs? What documentation are you referring to? 

Lots of people have used Pentax M42 lenses on their M42 mount K3s, check the archives here for plenty of discussions about lens recommendations etc. 

A small sample:

https://cinematography.com/index.php?/topic/65221-flange-distance-on-the-k-3/&tab=comments#comment-417662

https://cinematography.com/index.php?/topic/74571-krasnogorsk-3-peleng-17mm/&tab=comments#comment-478334

https://cinematography.com/index.php?/topic/33763-award-winning-film-using-k-3-and-m42-lenses/&tab=comments#comment-252412

 

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@Dom Jaeger

Two things:

1. This post was a question about changing the mount type and not about the physics of different lenses (most on this forum can’t handle that). Therefore, unless you know how to get the specifications on a lens design you shouldn’t try and tackle that. The documentation is public on the internet go and find it for yourself. I’m not doing it for you - sorry not trying to be rude but that is what this thread is trying to accomplish. I’ve said that several times. Re read or TL;DR

2. I specifically asked for advice from people who have shot with using still m42 mount lenses themselves and not the peanut gallery. Sad to say that’s all I have gotten. I’ve read a bunch about it yet have seen sub par information so I haven’t been convinced. We all know how to google so you sending me random links is irrelevant to everything I’ve stated on this thread. I’m not trying to be rude but let’s both be honest I’ve done the homework on that.

good luck in cinema friend 

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You asked for participatory advice then collectively dismissed us as sheeple absent practical experience? Good luck with your search for an obligatory peanut gallery that can validate your alleged superiority. Over out.    

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My apologies if anyone felt offended some of the replies assumed I didn’t understand or take the time and effort to try and solve this myself before asking. I’m sorry about the peanut gallery joke I thought it was funny but it wasn’t. I do appreciate all of the genuine responses. I didn’t mean to offend anyone. 

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On 11/2/2019 at 2:07 PM, Allen-Deon Saunders said:

@Will Montgomery

Hey Will,

You are right Pentax Super Takumar lenses are great. Do you have experience with this camera (K-3)? I am asking because even though it has an M42 mount it is far more technical than that. The Flange Focal distance from the mount to the film is about an inch. Most 35 mm cameras with a m42 mount type have a different distances for the image to be in focus (flange focal distance). Meaning, Unless someone has actual used a still lens on this camera, developed film, and then seen the results I cannot assume that option works. Do you have experience shooting with still lenses on this camera?

Looks like you've got a ton of responses. I can't speak for the technical mathematical details but like when I asked a local mechanic about a Ferrari sitting at dealer in West Virgina, his response was... "Runs good."  So that's what I'd say about the K3 and other Pentax lenses.

I've used 24mm, 35mm and 50mm Pentax Super Takumar lenses with the K3 with excellent results. When it was in focus in the viewfinder, it was perfectly in focus on the film. The 50mm was particularly sharp. I think I shot some Double X with it and was very pleased with the image quality and sharpness so I don't think the Flange Focal distance is an issue. Great inexpensive combination.

 

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On 11/4/2019 at 4:04 PM, Allen-Deon Saunders said:

@Will Montgomery

do you have any footage to share? I’d be interested in seeing some if you do. If not I understand. The footage from the film posted by someone else was shot entirely slightly out of focus. I was wondering if that had something to do with the FFD. 

I'll have to do some digging...the issue may be that it would have been transferred in SD but by a great colorist.

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I read your post since the first day you posted it, I have been working on modifying camera mounts and the K3 is one of my prospects. I shot several times using M42 lenses with the K3, actually I used to have a set of lenses for the camera that now my friend in LA owns, it is perfectly possible as everybody told you here, but I didn't know if I wanted to try to say something when you are so reluctant to hear what people have to say, specially when every thing people told you here is right. You are kind of right on the info that you have about FFD but those people actually have it right. It's not that complicated really, and as you pointed the information is online, but if you don't want to accept that info I don't know what you can do.

I shot 4 times using the K3 with my set of lenses: Zenitar 16mm f2.8, Vivitar 28mm f2.8, Super Takumar 50mm f1.4, I can't remember the brands on the other ones, but I had an 85mm f2.8, a 135mm f2.8 and a 200mm f4, so here is a setup from someone who had actually shot with a K3 and M42 lenses and here are a couple of HD samples of films shot with the K3, the first one is when the camera was regular 16 (cropped) and the second one converted to Super 16. All the lenses used on this two tests are m42 lenses desiged for still photography.

https://youtu.be/StGgzgXf-rg

https://youtu.be/bNXQs4DBOv0

Do I have experience with the K3? Well I converted the camera that I used to shot those films to S16 myself, I lubricated it and replaced the light seals, I bought the re-centering ring and I tried to adjust it to get it close the the appropriate FFD and I shot 4 rolls with the camera that are sharp and that let you see what the camera and the lenses can do. Every M42 lens that I had was different, they looked different and I wanted to move on to better cameras and lenses so I sold that one and the lenses. I recently got another K3 that I'm going to use to experiment with mounting lenses.

The information that other fellow members presented was correct. The FFD of the M42 mount is 45.46mm and it is the same on 35mm still photography cameras and on the K3. 

Getting a camera serviced is extremely important, because a technician will adjust the FFD, and the focusing screen distance. You have been talking about the FFD as if it were the only important part of the camera and it is not. You may have a FFD perfectly measured and if your focusing screen is not at the right distance you are going to see images out of focus on the viewfinder. You can have a perfectly set FFD and focusing screen distance and if you don't know how to adjust the diopter you may get out of focus images.

Now you think FFD is critical and it is, but the camera will still work if the FFD is not right on the spot. I did modify the mount on my K3 with sand paper and I never had the FFD adjusted and I did get sharp images every time, the difference is if the FFD is not set correclty you cannot trust the measuring distance (witness marks) on the lens so you cannot grab a measure tape measure at 10ft and then set the lens at the 10ft position and expect it to be right and your lens may not focus at infinity depending on where the actual distance is set.

Focal Flange Distance is important, yes, because if it is properly set you can trust your camera and lens even when your eye is telling you something different and you can get images in focus even without a viewfinder. If your friend didn't get images in focus it may be because the focusing screen was not at the right distance, or because the diopter was not set correctly. I really recommend "The 16mm Camera Book" (Underdahl) you can learn a lot from that book and you can learn how a camera is actually tested.

The best way to know if a camera is right on the spot even after being serviced (to make sure) is to shoot film. I do test my cameras at home shooting B&W film that I process and scan here. If FFD is correct, if the focusing screen is at the right distance and if the diopter is set using measurements and not your eye, you should have sharp images every time, and you should be able to tell by looking at the viewfinder.

I'm not sure I want to have a discussion or conversation with you about this. I hope you get some useful information, you can see some samples, so you can see it's possible. I'm sure other members have footage but they didn't want to deal with your attitude. People here are very nice and very, very helpful please don't disrespect them.

Edited by Ruben Arce
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