[drei3]

Could Ricoh/Pentax build a hybrid camera that uses an APS-C sensor a build-in, selectable lens turbo/speed booster? Perhaps something like the K-01 with the extra optics in front of the sensor. You'd be able to get a near FF field of view and even squeeze out an extra stop. I'm obviously not a camera designer, but I was wondering if it was feasible.


I apologize in advance if this is in the incorrect forum.

[Paul MaudDib]

Yes, build a MILC and release a first-party telecompressor for it. The Speed Booster is just a brand name for a telecompressor, and they're really common optical devices in astronomy/astrophotography.

Such cameras have been built in the past. For example, the Nikon E-series DSLR got full-frame FOV on 2/3" sensors, and the Minolta RD-175 got something like a M4/3 crop factor on a tiny 5x6.5mm sensor. And those are DSLRs no less, it's much easier on a MILC.

I've really been waiting for someone to fill this niche ever since I heard about the Speed Booster. It's really a good approach, you get more effective aperture out of your lens (brightness and DoF), you boost sharpness, and you get the native full-frame FOV on a cheap sensor. Basically, imagine what a telecompressor does, and the optical compromises it makes, and reverse them.

What I really, really want, though, is a full frame camera with a telecompressor that supports medium-format optics. I want to use my P67 105/2.4 as a super sharp 50/1.2. Or even brighter on APS-C!

[Fogel70]

Could Ricoh/Pentax build a hybrid camera that uses an APS-C sensor a build-in, selectable lens turbo/speed booster? Perhaps something like the K-01 with the extra optics in front of the sensor. You'd be able to get a near FF field of view and even squeeze out an extra stop. I'm obviously not a camera designer, but I was wondering if it was feasible.


I apologize in advance if this is in the incorrect forum.

I don't think there is much point in making a camera like this. APS-C sensor + tele compressor cost more than a FF sensor.
Using tele compressor also shortens the register distance, so you have to move the mount or sensor if having the option to disable the tele compressor in the camera.

[Paul MaudDib]

Using a telecompressor doesn't shorten the register distance per se. One way to implement this is to put an an adapter on a MILC - you take a DSLR-to-MILC adapter (eg EOS to NEX, in the Speed Booster) and you use some of the empty space inside the adapter to fit in the telecompressor optics. If you're talking about a DSLR, the register distance still doesn't change (eg Nikon E-series), the telecompressor acts as relay optics and optically alters the register distance to provide space for the telecompressor optics.

You're probably aware of this, just being clear. I agree that a "switchable" telecompressor is not practical. If you wanted to do that, you would build a MILC and then have two different adapters to K-mount, one is the Speed Booster adapter with the optics and the other is just a standard empty-tube adapter. If you built a DSLR body, it would probably have to be permanently one way or the other, but the Nikon E-series and Minolta RD-175 show that it is possible to build a telecompressor into a DSLR on a permanent basis, without altering the register distance of the mount.

Regarding cost, I think it would be reasonably affordable. The K-01 launched at $750, the Canon 6D at >$1500, a Metabones Speed Booster is <$750, so APS-C+adapter can match the cost of FF. That's kind of a worst-case scenario since both the camera company and the telecompressor manufacturer have to make their profit. China can clearly crank out (sub-par quality) telecompressors (Lens Turbo) for a very modest cost of <$150, and they're not losing money. I think if they were a mass-produced first-party product instead of a niche third-party product you could easily bring the Speed Booster cost from $750 down to sub-$400 while keeping the quality. I don't have a good reference point on what it would cost to build a telecompressed DSLR, but big sensors still aren't cheap, while it's certainly possible to make cheap optics with mass production.

Another interesting possibility, if you made a 645 mirrorless camera you could use the mirror space to put a telecompressor in there. Imagine a crop-sensor 645 that got the full-frame 645 field of view. You'd get savings from removing the mirror assembly, but let's say it cost an extra $1000 anyway, it would still be a tiny fraction of the cost of real 645-full-frame digital MF backs. That would truly be a killer offering. AF performance would suffer but who shoots sports on 645 anyway?

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Last edited by Paul MaudDib; 06-03-2014 at 01:48 PM.

[Fogel70]

Using a telecompressor doesn't shorten the register distance per se. One way to implement this is to put an an adapter on a MILC - you take a DSLR-to-MILC adapter (eg EOS to NEX, in the Speed Booster) and you use some of the empty space inside the adapter to fit in the telecompressor optics. If you're talking about a DSLR, the register distance still doesn't change (eg Nikon E-series), the telecompressor acts as relay optics and optically alters the register distance to provide space for the telecompressor optics.

You're probably aware of this, just being clear. I agree that a "switchable" telecompressor is not practical. If you wanted to do that, you would build a MILC and then have two different adapters to K-mount, one is the Speed Booster adapter with the optics and the other is just a standard empty-tube adapter. If you built a DSLR body, it would probably have to be permanently one way or the other, but the Nikon E-series and Minolta RD-175 show that it is possible to build a telecompressor into a DSLR on a permanent basis, without altering the register distance of the mount.

Not quite sure what you trying to say, but the speed boosters are a few millimeters shorter than adapters without optics. So using a speed booster the lens will be closer to the sensor than if using the lens on a DSLR. In a camera with a permanent telecompressor it don't matter much, but on a camera where you want to use with or without telecompressor the distance between the sensor and lens must change between these two modes.

[Na Horuk]

Its a very interesting idea! But this is really something I wouldn't expect to see from Pentax. Pentax is too conservative a company to do something quite like this

[ElJamoquio]

This would've been interesting for the K-01.

[richard balonglong]

If Pentax-Ricoh won't build a FF camera, at least they should build a quality K-mount telecompressor...

[Fogel70]

If Pentax-Ricoh won't build a FF camera, at least they should build a quality K-mount telecompressor...

The problem is that Pentax has no camera for a telecompressor designed for K-mount lenses. It requires a mirrorless camera with much shorter register distance than K-mount.

[Paul MaudDib]

The problem is that Pentax has no camera for a telecompressor designed for K-mount lenses. It requires a mirrorless camera with much shorter register distance than K-mount.

They do have (or had) a mirrorless camera with a nice, big empty space where the mirror box used to be...

It would mean giving up on the "XS" lenses that sit back into the throat of the camera, of course.

[Na Horuk]

It would mean giving up on the "XS" lenses that sit back into the throat of the camera, of course.

Its too bad those were given up on anyway.

[jogiba]

The Lens Turbo /Speedbooster .7*x focal reducer adapters like the PK-NEX work great on APS-C and m4/3rd mirrorless cameras but a real full frame sensor is the only way to go on a K-mount DSLR IMHO. There is no reason why Ricoh could not make a full frame DSLR for a few hundred more than the K-3 unless they think there would be no demand for it.

[konraDarnok]

I'd go one better, and have the built in telecompressor move, just like the AF1.7x teleconverter, then you'd get limited autofocus with manual glass, but there's zero market incentive for Pentax or any other dedicated manufacturer to do something like this.

If I had some venture capital to play with, I'd contract some Chinese company to build such a device, because it would be fun, and while we're at it, throw in a high speed leaf shutter.

[MMVIII]

This definitely looks like an attractive idea.
To expand it and bring it to the point of a whole system: take a page from the LX with interchangeable viewfinders and gxr with it's lensor modules and leave the (FF) sensor, but make it a sytem with interchangeable mount (and all varieties between it and the sensor), which can have some of the here mentioned modules - with AF converter, with mirror and hybrid AF, with shorter register distance, with 645 mount and telecompressor...
If they sell it configured as some options (35mmKAFDSLR, 35mmmicroKAFMILC, 645MILC(tc)...) and just give users the option to buy and change to other configurations it might not be over expensive and overcomplicated... At least they where not afraid to be modular with the gxr lately... ;-)

[Usuqa]

I'd go one better, and have the built in telecompressor move, just like the AF1.7x teleconverter, then you'd get limited autofocus with manual glass, but there's zero market incentive for Pentax or any other dedicated manufacturer to do something like this.

If I had some venture capital to play with, I'd contract some Chinese company to build such a device, because it would be fun, and while we're at it, throw in a high speed leaf shutter.

And nd filter