Pentax Q with K mount converter: weird possibilities

[spoorthy]

Imagine the Pnetax Q with a k mount teleconverter and a DA* 300 f4. That would give you an equivalent of a 1680mm lens!!! Now if only there was a way to hold it properly

 

[baldeagle21b]

You mean like with the built-in collar and a tripod?

 

[spoorthy]

I meant a regular converter that would allow a k mount lens to be used on the pentax q. It obviously hasnt been mad yet and probably wont

 

[Zvonimir Tosic]

It's not excluded that Pentax will release Q-to-K adapter. Because they don't precisely state, for whatever reason, it doesn't mean it won't come.

But this is also a chance for third party developers to make adapters for all different mounts, from Leica's M to Sony's new one, and so forth.

In fact, this will be a gold mine for some company smart enough to see the potential; even "everyday" people's DA200/2.8 lens suddenly becomes 1000/2.8 telescope.
It's simply amazing.

 

[snostorm]

Even if it isn't offered, it wouldn't be that hard to make one -- order a Q mounting plate for one of the Toy lenses (assuming the ones from the AF lenses would be more expensive) from Pentax parts, go to a B&M camera store and dig through their drawer of used K mount TCs and buy one for a couple of bucks and take the mounting plate off the front. Have a machinist turn a tapered aluminum tube of the right length (to correct the registration distance difference) with appropriate flanges on each end to mount the plates then paint the inside of the tube flat black. Should easily be under $100 USD total, and probably under $50.

I would only use it with relatively light lenses handheld (the D FA 100 Macro comes to mind -- a 553mm f2.8 dedicated 5.5:1 macro with some significant increase over the original working distance at 1:1!), and with ultra teles with tripod collars mounted on a pod -- so I'd just be hanging the body on the tripod mounted lens instead of the other way around.

I doubt if Pentax will release a K to Q adapter because they'd want to prevent opening themselves up to problems from people trying to hang big glass on the Q. By keeping this unauthorized they wouldn't suffer any product liability from this.

Also, don't forget that you'd retain the Minimum Focusing Distance of the lens, so the DA* 300 would be 1600+mm at 1.4m so the .24x original magnification of the lens multiplied by the 5.5x crop factor would yield 1.32:1 at 1.4m if I'm doing the math right. The problem with the DA series lenses is that they don't have aperture rings so you'd have to shoot wide open.

Scott

 

[brandrx]

Even if it isn't offered, it wouldn't be that hard to make one -- order a Q mounting plate for one of the Toy lenses (assuming the ones from the AF lenses would be more expensive) from Pentax parts, go to a B&M camera store and dig through their drawer of used K mount TCs and buy one for a couple of bucks and take the mounting plate off the front. Have a machinist turn a tapered aluminum tube of the right length (to correct the registration distance difference) with appropriate flanges on each end to mount the plates then paint the inside of the tube flat black. Should easily be under $100 USD total, and probably under $50.

I would only use it with relatively light lenses handheld (the D FA 100 Macro comes to mind -- a 553mm f2.8 dedicated 5.5:1 macro with some significant increase over the original working distance at 1:1!), and with ultra teles with tripod collars mounted on a pod -- so I'd just be hanging the body on the tripod mounted lens instead of the other way around.

I doubt if Pentax will release a K to Q adapter because they'd want to prevent opening themselves up to problems from people trying to hang big glass on the Q. By keeping this unauthorized they wouldn't suffer any product liability from this.

Also, don't forget that you'd retain the Minimum Focusing Distance of the lens, so the DA* 300 would be 1600+mm at 1.4m so the .24x original magnification of the lens multiplied by the 5.5x crop factor would yield 1.32:1 at 1.4m if I'm doing the math right. The problem with the DA series lenses is that they don't have aperture rings so you'd have to shoot wide open.

Hi Scott,

So, my FA*250-600mm f5.6 would become like.........DANG!....a freaking monster. :-D

I'm sold. :-D :-D :-D

Cheers.

Ron

--
Ron - 'We don't have time to go take pics this afternoon Carl.'
Carl - 'What do you mean? It will only take 1/1000s.'

'Keep your eyes looking forward. However, glance back now and then to see where you've come from. It will put a smile on your face.' ~ brandrx

 

[Myari]

In fact, this will be a gold mine for some company smart enough to see the potential; even "everyday" people's DA200/2.8 lens suddenly becomes 1000/2.8 telescope.

How are you calling it F2.8 when most of the light is wasted and is falling outside of the tiny sensor? Wide open the lens would be something like F16.

 

[Myari]

So, my FA*250-600mm f5.6 would become like.........DANG!....a freaking monster. :-D

It won't be "F5.6" anymore but something much slower/dimmer. That's for sure.

 

[Rod Herdman]

That's exactly what my Dad did many years ago and made a converter to fit K-mount lenses on his Pentax Auto 110. I borrowed it a while ago and used my 110 with my SMC-M 200mm f4 lens and it was awesome.

Rod

--
All I want is a digital back for my trusty K1000 . . .

 

[Stig Vidar Hovland]

So, my FA*250-600mm f5.6 would become like.........DANG!....a freaking monster. :-D

It won't be "F5.6" anymore but something much slower/dimmer. That's for sure.

So only looking at the center part of an image would make it dimmer? Don't think so.....

 

[paulkienitz]

Any long lens is going to throw most of the light from most of the scenery in front of it against the black interior of the lens barrel. That doesn't change the brightness, or the depth of field, of the part of the scene that you take a picture of. It's nothing but a form of cropping.

--
keepers: K10D, Sig 17-70, DA 55-300, FA 50/1.4 "Billy Bass"

discards: DA 50-200 "zipper", F 100-300, Sigma 135-400 "piglet", M 400/5.6 "the Great Truncheon"

 

[ManuH]

Any long lens is going to throw most of the light from most of the scenery in front of it against the black interior of the lens barrel. That doesn't change the brightness, or the depth of field, of the part of the scene that you take a picture of. It's nothing but a form of cropping.

Yes but terribly useful in practice. Cropping macro or tele shots is frequent on DSLR. And these small sensors are much more efficient at cropping. Try to crop your DSLR to the same size of this Q and then compare the results...

--



http://www.flickr.com/photos/ensh/

 

[snostorm]

It won't be "F5.6" anymore but something much slower/dimmer. That's for sure.

No it won't lose any light gathering capability. you're not extending the lens farther than the normal register distance, so it will perform as normal withouth AF amd
scott

 

[Roland Karlsson]

What a waste of good glass.

The lens is designed for a much larger image circle.

You will waste light as most of the image circle is falling outside the sensor.

You will waste resolution as it is much easier to make a lens that is only sharp over the smaller sensor.

Moreover - it will be awkward to handle with the small camera.

--
Roland

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[Roland Karlsson]

So only looking at the center part of an image would make it dimmer? Don't think so.....

Actually - in a sense it is. As the image is much smaller you have to enlarge it more.

Thats why the the smaller sensor has smaller pixels. And those smaller pixels collects less photons - i.e. are not so light sensitive.

--
Roland

support http://www.openraw.org/
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[Roland Karlsson]

It won't be "F5.6" anymore but something much slower/dimmer. That's for sure.

No it won't lose any light gathering capability. you're not extending the lens farther than the normal register distance, so it will perform as normal withouth AF amd
scott

Yes - its definitely losing light gathering capacity. If you make the sensor smaller more light falls outside it, so the total light gathering capacity decreases.

In practice the smaller sensor has smaller pixels. So - the decreasing light gathering capacity per pixel is the result of using a smaller sensor.

--
Roland

support http://www.openraw.org/
(Sleeping - so the need to support it is even higher)

X3F tools : http://www.proxel.se/x3f.html

 

[Zvonimir Tosic]

Zvonimir Tosic wrote:

How are you calling it F2.8 when most of the light is wasted and is falling outside of the tiny sensor? Wide open the lens would be something like F16.

No, it won't be so.
Light gathering ability of the lens and the size of its glass won't change.

 

[AngryCorgi]

So, my FA*250-600mm f5.6 would become like.........DANG!....a freaking monster. :-D

Hate to burst your bubble, but the diffraction + lens softness would result in very poor IQ. Putting an APS-C lens of ANY brand on a 1/2.3" sensor would be an unwise move. The lenses aren't designed to hold up to the scrutiny of those miniscule pixels. The equivalent APS-C sensor would be a 375MP sensor...most lenses can't even make full use of the > 20MP APS-C sensors used today.

--
-AC-

 

[awaldram]

So, my FA*250-600mm f5.6 would become like.........DANG!....a freaking monster. :-D

Hate to burst your bubble, but the diffraction + lens softness would result in very poor IQ. Putting an APS-C lens of ANY brand on a 1/2.3" sensor would be an unwise move. The lenses aren't designed to hold up to the scrutiny of those miniscule pixels. The equivalent APS-C sensor would be a 375MP sensor...most lenses can't even make full use of the > 20MP APS-C sensors used today.

Whilst I can agree on a technical level with everything you say there is more at play here.

Otherwise those plastic bubbles (lens) in front of really tiny sensor on camera phones would produce nothing but haze.

Oh wait they do seriously though there is other elements at play here.

--
-AC-

--
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[AngryCorgi]

Oh wait they do seriously though there is other elements at play here.

Trust me, Pentax won't release an adapter, and if someone does the optical quality of DSLR glass won't hold up well at all on this pixel-dense sensor.

--
-AC-