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12-20-2015, 03:57 PM   #1
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Pentax Q and Focal Reducer

Hello --

New to the Q, here. I have an original Pentax Q on its way and wanted to pose a few questions. My primary purpose for acquiring this camera is to use it with M42 lenses and leverage the 6x crop factor to see how it does with FL from 35 to 200mm. The thought of a 1200mm at f/3.5 is intriguing and almost to the point of being absurd! But along with using short-telephoto and telephoto lenses as super extreme telephotos, I'd like to be able to use M42's in a somewhat normal FL capacity. I've read a little bit on Focal Reducers, but have not really found any info as it relates to theri availability or use with M42's on a Q. Any insight or thoughts on the use of M42's on a Q and the use/viability of a Focal Reducer?

Thanks!!

12-20-2015, 04:25 PM   #2
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You will probably be a bit disappointed in the longer focal lengths on the Q. You can get good images, but it takes a lot of practice and tweaking. In my experience, it's much more useful for macro shooting and adapting things like cinema and tv lenses.

I don't know of any focal reducers for the Q system, but you might be able to go from m42 to m4/3 or Sony E with a reducer and then from there to Q.

It would be interesting to see if you can get decent resolution on the Q sensor, since reducers degrade I t a bit, and the photosites are so small.

---------- Post added 12-20-15 at 04:28 PM ----------

If you have access to a 3d printer, there is this:

M43 To Pentax Q Adapter (5XEUW4YKH) by charmlee
12-20-2015, 05:51 PM   #3
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The original Q has the most demanding sensor you can get on a Pentax,
at least as far as performance in the center of the image is concerned.
With most old telephotos, you'll need to remove fringes and CAs in post-processing.
The only lenses I've found to work really well are the Voigtlaender Apo-Lanthars.
12-20-2015, 06:02 PM   #4
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QuoteOriginally posted by lytrytyr Quote
The original Q has the most demanding sensor you can get on a Pentax,
at least as far as performance in the center of the image is concerned.
With most old telephotos, you'll need to remove fringes and CAs in post-processing.
The only lenses I've found to work really well are the Voigtlaender Apo-Lanthars.
I knew it wasn't up to the Q7 standards, but am disappointed to hear that it may be unsuitable for use with my vintage glass. :-(

I'll give her a go and see what I'm able to get with my Super-Tak 35 and 50 and M42 adapter. If it's a no-go I do have the 02 zoom with it and will either use it as designed, sell, or hand down to my youngest.

Maybe an M4/3 is really more what I needed.

12-21-2015, 09:44 AM   #5
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QuoteOriginally posted by ripper2860 Quote
I knew it wasn't up to the Q7 standards, but am disappointed to hear that it may be unsuitable for use with my vintage glass. :-(

I'll give her a go and see what I'm able to get with my Super-Tak 35 and 50 and M42 adapter. If it's a no-go I do have the 02 zoom with it and will either use it as designed, sell, or hand down to my youngest.

Maybe an M4/3 is really more what I needed.
The Pentax Q is a misunderstood creature. The original Q sensor is actually excellent for it's size even today. The Q7 is only marginally better, so we can group them together.
It's not that the sensor is unsuitable to use with vintage glass .. it's that few vintage lenses are good enough for the Q!

The correct way to think about this is to ask:

"Which lens will stand up best to the high resolution Q sensor?"

Because the sensor is 1/2.3" size, much smaller than APSC, all 12MP are concentrated is that small area. What this means is that the sensor is EXTREMELY demanding on the QUALITY of the glass put in front of it. This also means that any and all aberrations, CA, PF will show up more just because the sensor can and will resolve ANYTHING put in front of it.

So when it comes to using old school 35mm film era lenses, even DSLR APSC lenses, only the very VERY best will let that sensor shine! Lenses for m4/3 also fall in the same category.
The best legacy lenses for use with the Q are those for C mount movie cameras and also those designed for the tiny 8mm film cameras of old - those are D mount. This is because they were designed to resolve details just for that tiny format which is very close to the size of the Q sensor. It's actually pretty impressive that a tiny chrome old D mount movie lens the size of your little finger can produce incredibly sharp images with the Q. The limiting factor is the usability and skill of the person taking the pics. The real limiting factor for the Q has and continues to be a lack of (affordable) wide and super wide lenses for that tiny format!
12-21-2015, 10:48 AM   #6
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Yeah, I think a FL reducer would be awesome!

There would need to be a fair amount of bending to get the APSC or FF image circle down to the 1/2.3 or 1/1.7 inch sensor size, so I would expect some additional CA, but it seems like there is a lot of good and affordable lens designs that are being produced these days, so I'm sure it is possible.

The construction of a FL reducer would be limited in practice by the available space between the K-mount flange distance and the Q's flange. So, it probably can't have a super sophisticated FL reducer with dozens of elements. You wouldn't want an adapter that weighs 4 pounds anyway.

A K-to-Q focal length reducer would gain about 5 stops of light! Although at the end of the day, you are still cramming it onto a smaller sensor, so I guess the overall benefit is something of a wash. The cost gap between larger sensors and smaller sensors keeps on narrowing, so the window of opportunity keeps on getting smaller with time.

Another factor is the leaf shutter which is incorporated into most of the native Q lenses, as well as the official Pentax adapter. With a passive FL reducer, you would be limited to using the Q's electronic shutter. Probably not so much of a problem except when using flash, since the x-sync speed is really slow.

Whatever. I still think it would be fun to be able to use my K-mount collection, especially the DA Limiteds, without going full telephoto.
12-21-2015, 12:00 PM   #7
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QuoteOriginally posted by digital029art Quote
The Pentax Q is a misunderstood creature. The original Q sensor is actually excellent for it's size even today. The Q7 is only marginally better, so we can group them together.
You are taking into account that Pentax has grossly exaggerated the ISO values? E.g. ISO 800 on a Q is more like ISO 500. At least that's the case for the Q10: http://www.dxomark.com/Cameras/Pentax/Q10---Measurements

I'm not saying the Q is bad. I have it and I like it. But the sensor noise performance is, well... you can't expect miracles from a small sensor.

QuoteOriginally posted by digital029art Quote
It's not that the sensor is unsuitable to use with vintage glass .. it's that few vintage lenses are good enough for the Q!

The correct way to think about this is to ask:

"Which lens will stand up best to the high resolution Q sensor?"

Because the sensor is 1/2.3" size, much smaller than APSC, all 12MP are concentrated is that small area. What this means is that the sensor is EXTREMELY demanding on the QUALITY of the glass put in front of it. This also means that any and all aberrations, CA, PF will show up more just because the sensor can and will resolve ANYTHING put in front of it.
Yup, that's true. That's why it's actually easier to produce well-performing lenses for bigger sensor platforms.

Last edited by starbase218; 12-21-2015 at 12:44 PM.
12-21-2015, 06:15 PM   #8
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QuoteOriginally posted by digital029art Quote
The Pentax Q is a misunderstood creature. The original Q sensor is actually excellent for it's size even today. The Q7 is only marginally better, so we can group them together.
What is your basis for this statement?

If Q7 is truly not an improvement, then the Sony engineers must have had a couple of really bad years. The Q7 was built two years after the Q, which means at least a generation of Moore's Law improvement in the sensor and supporting hardware. In addition, the Q7's semsor is physically larger than the Q's sensor, so each Q7 photosite is roughly 45% larger in area than each Q photosite.


Last edited by reh321; 12-21-2015 at 09:11 PM.
12-22-2015, 08:11 AM   #9
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There's isn't much difference in actual picture taking between 1/2.3 and 1/1.7 sensors. Not much reason to invoke Moore's Law since that really applies to computing power in general, not CMOS sensors. Besides Moore, there's something called marketing and economics which has much more influence on what is actually produced and sold.
12-22-2015, 08:44 AM   #10
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I disagree. Owning both, I can attest that the performance of the Q7 is quite obviously and noticeably better than that of the original Q, and it goes beyond just megapixels. DR and color rendition are both better as well. The larger photosite size also gives about an extra stop of latitude before diffraction becomes obvious as well.
12-22-2015, 09:25 AM   #11
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QuoteOriginally posted by digital029art Quote
There's isn't much difference in actual picture taking between 1/2.3 and 1/1.7 sensors. Not much reason to invoke Moore's Law since that really applies to computing power in general, not CMOS sensors. Besides Moore, there's something called marketing and economics which has much more influence on what is actually produced and sold.
Moore's Law is completely applicable - it apples to semi-conductors in general, and anytime you see "CMOS", you're talking about semi-conductors. Moore's Law is why each generation of digital cameras is noticeably better than the previous generation, why the cameras we have today are vastly better than the ones we had a decade ago, and why each year people here hope for a replacement for the flagship camera that they had greeted with great joy a year or two earlier. What is produced and sold today depends primarily on the increased capacity that Moore's Law has provided, which allows designers to provide today what their dreams had reached for last year.

Moore's Law is what allows each generation of sensor to have more MP and do a better job of collecting the light,

Last edited by reh321; 12-22-2015 at 09:32 AM. Reason: added thought
12-22-2015, 11:00 AM - 1 Like   #12
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This is a complete misapplication of "Moore's Law"... which, BTW, is not a "law", but rather merely an observation (and future estimation) by one of the founders of Intel.

Moore's Law states that the number of transistors in a given area will double within a specific period of time - and please note that the amount of time attributed to Moore's Law has been changed over the years, so Moore's Law is not immutable. Moore's Law does not apply to the ability of the pixels in an image sensor to capture light, nor does it apply to reducing electronic crosstalk or on-chip noise reduction.

Also, Moore's Law is no longer used for projection purposes in the technology field. It's been several years since companies like Intel and (especially) AMD have been able to keep up with it.
12-22-2015, 11:01 AM   #13
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Maybe Santa will bring you the latest in Moore's Law then reh321 !?

If you wanna split hairs than I guess we'll have to talk about the definition of "marginally better" Q vs Q7 .. yawn!
12-22-2015, 11:58 AM   #14
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QuoteOriginally posted by luftfluss Quote
This is a complete misapplication of "Moore's Law"... which, BTW, is not a "law", but rather merely an observation (and future estimation) by one of the founders of Intel.

Moore's Law states that the number of transistors in a given area will double within a specific period of time - and please note that the amount of time attributed to Moore's Law has been changed over the years, so Moore's Law is not immutable. Moore's Law does not apply to the ability of the pixels in an image sensor to capture light, nor does it apply to reducing electronic crosstalk or on-chip noise reduction.

Also, Moore's Law is no longer used for projection purposes in the technology field. It's been several years since companies like Intel and (especially) AMD have been able to keep up with it.
This discussion is silly. As a long-time computer professional, I am well aware of Gordon Moore's contributions to my profession, and how his observation has played out over time, and I have been a participant in how hardware engineering, and those who work with hardware, have been affected.

Attribute it to whatever you want. No reasonable person doubts that there has been a consistent improvement in sensors over the years.

In the daze of film, I would typically use a camera for a decade before upgrading, so when I bought my Canon Rebel on Black Friday 2007, I penciled in Back Friday 2017 as when I would replace it. I bought my Pentax Q-7 just about a year ago. When my wife and I visited our daughter in San Diego in March, I quickly discovered that the Q-7 was much much better for indoor natural-light pictures than my now eight-year old Canon was. A few months later, when that Canon died, I was quite comfortable using the Q-7 as its backup (usually I would have my previous primary camera to backup my primary camera, but that would have meant going back to film) until I purchased a new primary camera, because in all circumstances that Q-7 had proven itself as being at least as good (in everything except viewfinder) as the Rebel had been.

A few weeks ago, my wife and I went to a Madrigal Dinner at the college where she is an administrator and I teach part-time. We were in the second row; the lady in the first row, and almost directly ahead of us, took lots of flash pictures with her Nikon DSLR. After the dinner, I asked her why she used so much flash, because it washed away the candle-light atmosphere that the producers had worked so hard to achieve. She showed me that natural light pictures were not working out well (noticeably noisy even on her LCD). When she looked at my pictures, she gasped and asked me to email them to her; the first picture she saw was of her daughter's solo.

I am not claiming that a Q-7 is superior to a contemporaneous Canon or Nikon DSLR, but it does demonstratively provide better low-light images than a six years older Canon DSLR, or even a three years older Nikon DSLR (nearly the time difference between Q and Q-7). That is the kind of progress we all have observed; most of that is purely in hardware, partly in how putting more devices (a sensor contains more than just the light-catching elements) on the sensor, and having more room in which to arrange things, has enabled the engineers to improve all aspects of what those sensors do.

If you wish to discuss this further you certainly may do so, but claiming "marginal" improvement between Q and Q-7 is silly, just as it would be silly to claim that a Q-S2 would not demonstrate similar progress in sensor development. That is all I was saying, and that is all I will say.
12-22-2015, 12:17 PM   #15
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Well, I certainly did not intend to fan the flames of debate to such an extent!! :-O

I did receive my Q today and will certainly give it a good going-over to see just how it will meet my expectations. So far, I can say it is a very tiny and impressive bit of kit. It will take a bit of time and effort to master shooting my vintage glass on this tiny marvel of engineering, but I do know it will be fun figuring out what I can and cannot do with this little guy!
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