[asw66]

What's the advantage off that?

The 645 mount is huge and there are K to 645 adapters so there is no need at all for it....
Besides that K mount lenses are easier and cheaper then 645 lenses.

OK, unless I've misread you, you're asking for a mount with a wider diameter than K. I'm pointing out that Pentax already has such a mount ....

Sure, the flange is deeper than K mount, but that's a different issue altogether. And since the mount is completely over-sized for a FF body, there's plenty of room for sensor-based shake reduction. Moreover, this approach has obvious advantages in terms of upgrade paths and minimising the number of different mounts to support.

By the way, are there really adapters for mounting K lenses on 645 bodies? Because that's what I'm talking about here, not an adapter to mount a 645 lens on K body.


(Please note that I'm just treating all this as a theoretical exercise, since I don't share your pessimism about K mount.)

[Anvh]

Rather then misread you're missing the point.

The K-mount and 645 mount has those dimension because it fits the sensor and you've enough room for the mirror.
With fit for the sensor i mean that normal lenses can be made with relative ease, what you want is register distance roughly the same as the focal length for the normal lens and a large enough lens diameter.

The register has most influence on the lens design and the mount diameter has more to do with the fastest aperture you can get.
So if you use FF sensor with 645 mount you've a problem, it would mean that for 43mm lens you need to use wide angle design and those are more expensive.

Anyway i was talking about the APS-C sensor since that's the most economical at the moment.
If pentax decide to only use APS-C sensor for their DSLR, i would like to see a mount designed for that sensor so that lenses become cheaper and faster compared to what they are now.
So that means a register distance around 30mm and a large enough diameter.
Not only would it benefit the lenses, the camera will also be slightly smaller and MILC cameras like the K-01 will be slightly thinner and with the faster lenses it would mean they can compete with APS-C in the professional market more.

[Kunzite]

What's the advantage off that?

The 645 mount is huge and there are K to 645 adapters so there is no need at all for it....
Besides that K mount lenses are easier and cheaper then 645 lenses.

So you want a small big mount, in order to mount cheap expensive lenses?

There is no point, really, other than the thought Pentax could go mad, abandon all their decades-long hard work and their customers and re-start from scratch. Why are we even discussing this?

Btw, the "mount designed for digital" was the 4/3 - I remember all the marketing hype about it. It didn't work.

asw66, mounting K lenses on a 645 body (even 645D) means:
- heavy vignetting, only parts of the image could be used
- losing infinity focus
A 645D body with a "FF" sensor would be an epic fail, because it would use only medium format, very expensive (and not very fast) lenses.
Please, let's stop looking for "solutions" to problems that don't exist.

[eurostar]

Rather then misread you're missing the point.

The K-mount and 645 mount has those dimension because it fits the sensor and you've enough room for the mirror.
With fit for the sensor i mean that normal lenses can be made with relative ease, what you want is register distance roughly the same as the focal length for the normal lens and a large enough lens diameter.

The register has most influence on the lens design and the mount diameter has more to do with the fastest aperture you can get.
So if you use FF sensor with 645 mount you've a problem, it would mean that for 43mm lens you need to use wide angle design and those are more expensive.

Anyway i was talking about the APS-C sensor since that's the most economical at the moment.
If pentax decide to only use APS-C sensor for their DSLR, i would like to see a mount designed for that sensor so that lenses become cheaper and faster compared to what they are now.
So that means a register distance around 30mm and a large enough diameter.
Not only would it benefit the lenses, the camera will also be slightly smaller and MILC cameras like the K-01 will be slightly thinner and with the faster lenses it would mean they can compete with APS-C in the professional market more.

OR you make recessed lenses which protrudes inside the mount just like the register distance would be the correct one for APS-C, and it become exactly the same.

[Blue]

Lol, you guys: even a little gentle teasing is too much. In the meantime, tell me where the K-01 is on the list of the best-selling compact system cameras on your local Amazon. Unless someone thinks that a 5% market share is as good as it is ever going to get, the question is how to grow: what is going to draw those new to Pentax to a Pentax camera. My point is that "Anything you like providing it is K-mount" isn't necessarily the answer. Clearly it will be in some circumstances but not all, as the tale of the K-01 suggests. There's really nothing wrong with looking at a few what-ifs.

I guess you missed the > . At any rate, my point was that sinking the K-mount for the K-01 and possible successors isn't a good move. Plus, the 5% applies to dSLR. The K-01 hasn't been on the market as long as the GF2 or GF3 so comparing sails at this point doesn't mean much. However, I expect the K-01 to do well in Japan and Europe. For the record, my E-P1 isn't pocketable except with a pancake it will fit in a coat pocket. With the 12mm/2, 45/1.8 or 75/1.8, not happening. Besides, that is the other direction from FF anyway.

[Blue]

I've always wondered if something like titanium in the barrel construction might allow for thinner walls on a lens and make such a lens possible. It seems like if they can make a 600 f/4 which has a 150mm aperture, something like an 85 f/1.2, which only has a 70mm opening should be possible. Maybe there's more room for elements to correct aberration in the 600, I don't entirely understand the physics of it.

Nikon faces the same issue with a super fast 85mm. Nikon has a couple of 85/1.4 and 1.8 lenses in their current catalog as well as the past. Pentax has had a couple in the past also.

[Anvh]

There is no point, really, other than the thought Pentax could go mad, abandon all their decades-long hard work and their customers and re-start from scratch. Why are we even discussing this?

Btw, the "mount designed for digital" was the 4/3 - I remember all the marketing hype about it. It didn't work.

It's not like you need to since you can your lenses if they provide a perfect working adapter, i really don't see a problem some have with using an adapter, did a adapter miss thread you in the past or something like that?
And i'm discussing it because it would be an alternative for going FF.

No idea why 4/3 failed but if you look at the whole system it really wasn't bad.
What is interesting is to see how many adapters there are for this system, you can fit almost any lens on it which in itself is of course very interesting.
It's sad they stop making cameras or i would have looked at it seriously.

OR you make recessed lenses which protrudes inside the mount just like the register distance would be the correct one for APS-C, and it become exactly the same.

Problem with this is that your lens can never have the width needed to get a fast enough aperture so you can compete with FF.
So yes register wise it's the same but the mount diameter is much smaller.

[Rorschach]

What I don't understand is why hasn't Pentax made 6x7 to K-mount and 645 to K-mount tilt adapters. Instead we are forced to get ridiculously expensive Zoerk stuff or not-so-well-made Pentacon Six to K-mount adapters and Pentacon Six lenses.

[ElJamoquio]

Nikon faces the same issue with a super fast 85mm. Nikon has a couple of 85/1.4 and 1.8 lenses in their current catalog as well as the past. Pentax has had a couple in the past also.

Pentax has a 77mm f/1.8. But they Pentax don't have an 85mm f/1.6. Pentax doesn't have an 85mm f/1.4, either. I think changing a mount to go from max 1.4 to max 1.2 is a bad idea.

[Anvh]

third party company did make one for 645.
I believed it cost $180.

[Blue]

Pentax has a 77mm f/1.8. But they Pentax don't have an 85mm f/1.6. Pentax doesn't have an 85mm f/1.4, either. I think changing a mount to go from max 1.4 to max 1.2 is a bad idea.

You missed the point and everyone on this board knows Pentax has the FA 77/1.8 ltd. However, we were discussing that the only real argument that can be made against the k-mount and Nikons f-mount is it makes it a challenge to design an 85/1.2. However, Pentax has had a couple of 85/1.4 lenses in the past (FA* 85/1.4 IF and A* 85/1.4). Nikon has a current af 85/1.4 and 1.8 and several others in the past. We were talking about the f1.2 barrier in this FL. I wasn't the one suggesting changing mounts. I just was pointing out that this is really the only thing to gain. I don't think you will see Nikon or Pentax dumping their bayonets. Besides, an update of the FA* 85/1.4 or A* would be a good option.

[Blue]

What I don't understand is why hasn't Pentax made 6x7 to K-mount and 645 to K-mount tilt adapters. Instead we are forced to get ridiculously expensive Zoerk stuff or not-so-well-made Pentacon Six to K-mount adapters and Pentacon Six lenses.

It could be that the 45mm 67 lenses are wide on the 67 but merely normal on the 35 format. Some argue that even the K 28mm shift that Pentax made isn't wide enough on aps-c.

[beholder3]

[deleted]

[ElJamoquio]

You missed the point and everyone on this board knows Pentax has the FA 77/1.8 ltd. However, we were discussing that the only real argument that can be made against the k-mount and Nikons f-mount is it makes it a challenge to design an 85/1.2. However, Pentax has had a couple of 85/1.4 lenses in the past (FA* 85/1.4 IF and A* 85/1.4). Nikon has a current af 85/1.4 and 1.8 and several others in the past. We were talking about the f1.2 barrier in this FL. I wasn't the one suggesting changing mounts. I just was pointing out that this is really the only thing to gain. I don't think you will see Nikon or Pentax dumping their bayonets. Besides, an update of the FA* 85/1.4 or A* would be a good option.

I understood your point and I was making a separate point. Let me restate that point. Unless we see Pentax pushing up against the limits of the mount NOW, it doesn't really make sense to change the mount now.

This point wasn't intended as a direct rebuttal to your point.

[ENicolas]

Because some of us are just as fanatical about APS-C as you are with FF. So I have an equally long list why I need to stick with APS-C.

Yeah - I'm an APS-C fan because I'm also a breakfast, lunch, and dinner fan, and to afford FF+Lenses I'd have to give two of those up.