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01-12-2016, 09:53 AM   #1
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Q7 Versus Q Resolution At Same Focal Length?

I just picked up an 06 zoom, and used it for the first time during an orchestral concert. With the full F2.8 aperture at the long end, I was quite pleased with the results I obtained at ISO 1600 on my Q. I am considering getting a Q7 (or Q-S1) and realize the increased field of view will provide less reach with the 06 (205 mm v 254 mm equivalent). However, the information I have gathered suggests the larger sensor in the Q7 may still provide better resolution at the same lens focal length, even though a feature in the image (a head for example) covers less pixels?

The forums in depth review of the Q7 includes a comparison versus the Q at the same focal length and subject distance.
Pentax Q7 Review - Compared to the Q | PentaxForums.com Reviews
The extracts of the two pictures both have the same relative feature size and the same dimensions (444 x 272), so I assume they have been scaled? Does anyone have straight out of camera images from a similar comparison that would allow comparison at the pixel level? I have searched through the threads in the forum and have found comments about similar tests but no actual images. My apologies if I missed something.

At first glance, it would seem logical that the smaller pixel size in the original Q would provide more detail at the same focal length. However, the performance of the sensor and any noise reduction applied may cancel this out. The smaller sensor will also run into diffraction issues first. I like the increased reach of the 06 on the Q but I am certainly willing to crop down the image from a Q7 (or Q-S1) if the resolution is there. Thanks in advance for your help!

01-12-2016, 10:15 AM   #2
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QuoteOriginally posted by reduno Quote
I just picked up an 06 zoom, and used it for the first time during an orchestral concert. With the full F2.8 aperture at the long end, I was quite pleased with the results I obtained at ISO 1600 on my Q. I am considering getting a Q7 (or Q-S1) and realize the increased field of view will provide less reach with the 06 (205 mm v 254 mm equivalent). However, the information I have gathered suggests the larger sensor in the Q7 may still provide better resolution at the same lens focal length, even though a feature in the image (a head for example) covers less pixels?

The forums in depth review of the Q7 includes a comparison versus the Q at the same focal length and subject distance.
Pentax Q7 Review - Compared to the Q | PentaxForums.com Reviews
The extracts of the two pictures both have the same relative feature size and the same dimensions (444 x 272), so I assume they have been scaled? Does anyone have straight out of camera images from a similar comparison that would allow comparison at the pixel level? I have searched through the threads in the forum and have found comments about similar tests but no actual images. My apologies if I missed something.

At first glance, it would seem logical that the smaller pixel size in the original Q would provide more detail at the same focal length. However, the performance of the sensor and any noise reduction applied may cancel this out. The smaller sensor will also run into diffraction issues first. I like the increased reach of the 06 on the Q but I am certainly willing to crop down the image from a Q7 (or Q-S1) if the resolution is there. Thanks in advance for your help!
I have a Q and Q-S1, and the 06 lens -- I can try to get shots of what you are asking sometime soon. Maybe tonight.
01-12-2016, 11:06 AM   #3
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QuoteOriginally posted by enoeske Quote
I have a Q and Q-S1, and the 06 lens -- I can try to get shots of what you are asking sometime soon. Maybe tonight.
That would be great. I was running wide open at F2.8 and 45 mm on the 06.
01-12-2016, 11:09 AM   #4
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Like the review says, the Q7 should still be better. I'll see if I can dig up the original files used in the review


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01-12-2016, 12:41 PM   #5
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QuoteOriginally posted by reduno Quote
I just picked up an 06 zoom, and used it for the first time during an orchestral concert. With the full F2.8 aperture at the long end, I was quite pleased with the results I obtained at ISO 1600 on my Q. I am considering getting a Q7 (or Q-S1) and realize the increased field of view will provide less reach with the 06 (205 mm v 254 mm equivalent). However, the information I have gathered suggests the larger sensor in the Q7 may still provide better resolution at the same lens focal length, even though a feature in the image (a head for example) covers less pixels?

The forums in depth review of the Q7 includes a comparison versus the Q at the same focal length and subject distance.
Pentax Q7 Review - Compared to the Q | PentaxForums.com Reviews
The extracts of the two pictures both have the same relative feature size and the same dimensions (444 x 272), so I assume they have been scaled? Does anyone have straight out of camera images from a similar comparison that would allow comparison at the pixel level? I have searched through the threads in the forum and have found comments about similar tests but no actual images. My apologies if I missed something.

At first glance, it would seem logical that the smaller pixel size in the original Q would provide more detail at the same focal length. However, the performance of the sensor and any noise reduction applied may cancel this out. The smaller sensor will also run into diffraction issues first. I like the increased reach of the 06 on the Q but I am certainly willing to crop down the image from a Q7 (or Q-S1) if the resolution is there. Thanks in advance for your help!

this probably won't help you but i feel it lends to the sensor on the Q versus the Q7 (q-k adapter, sigma 500mm 4.5 ex)...it is manual focus so can get variation from that....birds not on same branch but done on tripod with same set up...the iso are different 125 versus 100 as well as shutter 1/10 versus 1/20...bet you can guess which is q and q7...answer at the bottom










first is Q , second Q7...i think both are respectable but Q7 looks better
01-12-2016, 02:10 PM   #6
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QuoteOriginally posted by Adam Quote
Like the review says, the Q7 should still be better. I'll see if I can dig up the original files used in the review
Thanks Adam. That's the type of help and support that makes these forums such a great resource.

QuoteOriginally posted by pearsaab Quote
first is Q , second Q7...i think both are respectable but Q7 looks better
Thanks too Pearsaab. The Q7 image certainly looks sharper. I am assuming both images were cropped and re-sized to get the 1600 x 1200 (1197) images?
01-12-2016, 02:30 PM   #7
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QuoteOriginally posted by reduno Quote
Thanks Adam. That's the type of help and support that makes these forums such a great resource.



Thanks too Pearsaab. The Q7 image certainly looks sharper. I am assuming both images were cropped and re-sized to get the 1600 x 1200 (1197) images?

no i do not believe they were cropped...this is the size i can post of the forum...you can see the original on flickr but is has been awhile since i did the comparison...i can also try to do the 06 lens but i don't get home from work in time before it gets dark
01-12-2016, 02:42 PM   #8
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QuoteOriginally posted by pearsaab Quote
no i do not believe they were cropped...this is the size i can post of the forum...
Thanks, I had assumed that since the bird filled roughly the same area of the frame in both images, that they must have been cropped or scaled differently, to compensate for the different sensor sizes on the Q and Q7.

01-12-2016, 03:29 PM   #9
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QuoteOriginally posted by reduno Quote
At first glance, it would seem logical that the smaller pixel size in the original Q would provide more detail at the same focal length.
Nothing could be further from the truth. Actually the opposite is true. The larger the pixel site the more light it can capture, the less noise it produces resulting in a higher quality image. There are many WEB sites that explain this.
01-12-2016, 04:23 PM   #10
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You are mistaken.

Detail (resolution),and dynamic range/signal to noise ratio are opposite sides of the same coin. All else being equal, and presuming the lens is capable of outresolving the smaller photosites, a sensor with the smaller photosites will have more detail for an equal-sized (in absolute, not pixel terms) cropped portion of an image circle. However, the sensor with the larger photosites will have better DR/noise characteristics.

The Q7 sensor is a later generation than that in the Q and already has more efficient signal detection characteristics at an area of equal size. Additionally, its photosites are larger, and it grabs a larger portion of the image circle, meaning that the overall amount of detail in a full Q7 image (which is larger in MP terms than a Q image) and the dynamic range/noise both significantly outpace the original Q.

QuoteOriginally posted by CWRailman Quote
Nothing could be further from the truth. Actually the opposite is true. The larger the pixel site the more light it can capture, the less noise it produces resulting in a higher quality image. There are many WEB sites that explain this.

Last edited by dcshooter; 01-13-2016 at 08:08 AM. Reason: typo
01-12-2016, 10:28 PM   #11
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Here are the original files of the AC unit:

https://themotec1.netfirms.com/Users/Hosted/cdn/PentaxQ/vent/vent_Q_IMGP0074_a.tif

https://themotec1.netfirms.com/Users/Hosted/cdn/PentaxQ/vent/vent_Q_IMGP0074.DNG

https://themotec1.netfirms.com/Users/Hosted/cdn/PentaxQ/vent/vent_Q7_IMGP0606_a.tif

https://themotec1.netfirms.com/Users/Hosted/cdn/PentaxQ/vent/vent_Q7_IMGP0606.DNG

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01-13-2016, 07:14 AM   #12
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QuoteOriginally posted by dcshooter Quote
Detail (resolution),and dynamic range/signal to noise ratio are opposite sides of the same coin. All else being equal, and presuming the lens is capable of outresolving the smaller photosites, a sensor with the smaller photosites will have more detail for an equal-sized (in absolute, not pixel terms) cropped portion of an image circle.
I have to agree with dcshooter, especially with the key comment "all else being equal". In reality the sensors are not ideal and everything is certainly not equal. In my case I am particularly interested in higher ISO performance, where the noise of the smaller sensor starts to dominate. Even with 40% less pixels in a given area of the image on the sensor, the Q7 appears to provides a better picture. With the 06 lens I was still able to get acceptable results at ISO 1600 on the Q. The F2.8 aperture is key, as it gives me an 1 or 2 stop advantage over my APSC cameras where I am limited to F4.0 or F5.6 at the long end (sorry no DA 200mm F2.8).

QuoteOriginally posted by Adam Quote
Here are the original files of the AC unit:
Thank you Adam for posting the links. The raw files appear to corroborate with the findings pearsaab made. I think it's time to look for a good deal on a Q7 or Q-S1.

Thanks again to all for your comments.
01-13-2016, 04:51 PM   #13
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QuoteOriginally posted by reduno Quote
I think it's time to look for a good deal on a Q7 or Q-S1.
The Q-S1 has clearance pricing at B&H:
Pentax QS1 Mirrorless Digital Camera (Pentax QS1 Body, Black) B&H

I haven't followed the Q market recently but this is a good price compared to what the Q7 was selling for in the months after its launch.

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01-14-2016, 10:14 AM   #14
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QuoteOriginally posted by Adam Quote
The Q-S1 has clearance pricing at B&H:
Thanks for the link Adam. I have been very happy with my previous purchases from B&H. I also like the gunmetal and black version Adorama has but the kit is quite a bit more expensive. The catch for me living in NY state, is I also get to pay the 8.75% sales tax.
03-03-2016, 10:30 AM   #15
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It appears many posters misunderstood OP's question.
The question was about tele reach, not what you get with 1/1.7" and 1/2.3" if you come close enough for subject to fill the whole frame.
And about 15-45 zoom, not SLR lenses - which are designed for larger sensor and are unable to use advantages or higher pixel density.
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