K5 ISO worth the upgrade form K7? Compare and decide.


amoringello

Link Posted 10/11/2010 - 23:54
Just got my K5 a couple of days ago. Really haven't had much chance to play hard with it, but had to do a quick ISO test between it and my K7.

Have to say the K7 isn't really all that bad and perhaps not all *too much* worse than the K5 in good light.
But I will appreciate and be able to use the expanded ISO and other features of the K5.

I have two sets of tests.
One in natural lighting near a bay window - about 4pm. So not too bright but also before lighting conditions changed within the two minutes to take the photos.
The other is under fluorescent lighting in the basement. This lower light shows more severe artifacts with the K7 at higher ISOs.

Otherwise for each, the aperture remained constant.
Shutter speed adjusted to compensate for change in ISO.

Anyway, I hope someone else finds this interesting...
I added no processing above what LightRoom3 does on its own.

http://moringello.com/public/K5_vs_K7_ISO.html

http://moringello.com/public/K5_vs_K7_ISO_LowerLight.html

If you click on the thumbnails, the 100% crop images will be displayed.
I hope they give a good idea of the noise and detail.
Last Edited by amoringello on 10/11/2010 - 23:56

K10D

Link Posted 11/11/2010 - 00:09
First set appear to show the K7 has warmer colour or is it down to white balance?

Either way, we do not have consistency from model to model do we?

Detail on the K5 is good in the first set yet the K7 appears better.

In lower light at ISO 200, the K7 nails it.

The K7 loses out at the higher ISO low light situation but at good light, low ISO, I prefer it.

Others may/will differ.

Best regards

amoringello

Link Posted 11/11/2010 - 00:28
Yeah, not quite sure why. Both on auto white balance. But I do see that the color is consistently a bit different than the K7 under various environments. I guess I'll have to take them both outdoors and play with different white balances at some point. (If I'm going to keep my K7 as a backup, it won't be very good if the balance is inconsistent across the board)

Not really sure about the focus issue either. I agree the K5 seems softer. Camera was on auto focus, so it should have "fixed" itself if I was off on one. I may go back and re-do a few key frames and see if I can figure that part out. Especially ISO 100 where I do most of my work. (ergh!!)

I actually like the K7 up to ISO 800 in the brighter light. In the real world I've done well up to ISO 1000 in daylight and even with stage lighting, so at least things are consistent there.

I've been locked up in the house and work for the week. By the weekend I hope to get some daylight photos and see how the quality holds up between them there.

Anyway, I like the side-by-side compare of noise, regardless of slight softness and color issues.
I hope it is still of some slight interest to someone.
Last Edited by amoringello on 11/11/2010 - 00:28

dougf8

Link Posted 11/11/2010 - 00:52
Thanks for that Amoringello.

I don't take the K-7 above ISO800 normally and where I can I keep it as low as poss for the detail and quality.

I'm backing down from "must have asap" to "lets see the price settled".
Lurking is shirking.!

K10D

Link Posted 11/11/2010 - 00:55
No problem, once you decide on a set of test parameters/conditions, you'll see any differences that cannot be put down to unknowns.

Use manual on everything, since you are only comparing the images, why have AF, AWB etc? Remove any variables.

Best regards
Last Edited by K10D on 11/11/2010 - 00:57

thoughton

Link Posted 11/11/2010 - 10:23
Interesting. Were these taken in RAW?
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

amoringello

Link Posted 11/11/2010 - 10:56
Yeah, sorry some more details..
All shot in RAW. As stated no extra processing above LightRoom3's defaults.
100% crop converted to JPEG at 100% quality.
The images were at F7.1, various ISO and shutter-speed adjusted appropriately.
Baseline exposure: ISO 100 @ 1 second. (for both tests, thus brighter light test is more well exposed)

If time is on my side this weekend, I'll give these a second go and double check the focus and WB before I tear everything down.

thoughton

Link Posted 11/11/2010 - 10:59
Is it possible your lens needs AF calibration on the K5, and you have already done it on the K7?
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

amoringello

Link Posted 11/11/2010 - 11:20
Hmmm, maybe. But I don't like to blame the equipment until I really make sure its not my fault.

I suppose I could use LiveView with contrast focus. My guess is that lens calibration would not fall so much into play as the focus is occurring via the sensor itself.

I have not read much on that focus mode (I rarely use Live View), but I wonder if that would be a reliable way to tell if the standard focusing is off or not. Any ideas?

thoughton

Link Posted 11/11/2010 - 11:23
I don't know the answer to the Live View question, but on reflection I guess at f7.1 it's pretty unlikely to be an AF calibration error.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

johnriley

Link Posted 11/11/2010 - 11:25
Moved to digital forum.

Pentaxophile

Link Posted 11/11/2010 - 12:59
This is the kind of side by side test people have been waiting to see. Confirms the K-5 sensor is 'superior', but that the K-7 isn't quite ready for the bin yet!

The softness on the K-5 samples may be a stronger AA filter at work. BUT I am sure the softness would not really translate into prints that have been post processed. Just like the noise on the K-7 would not, up to ISO800 if not beyond in some cases.
[link=https://500px.com/will_brealey/[/link]

thoughton

Link Posted 11/11/2010 - 13:00
I also wondered about the AA filter, but I've heard (read, actually) speculation that the AA filter is weaker on the K5 than previous models.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27, Macbook Pro 17, iPad, iPhone 3G
Flickr Fluidr PPG Street Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!

Anvh

Link Posted 11/11/2010 - 16:21
amoringello wrote:
I suppose I could use LiveView with contrast focus. My guess is that lens calibration would not fall so much into play as the focus is occurring via the sensor itself.

Yes you're correct, that would be perfect
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

Anvh

Link Posted 11/11/2010 - 16:23
Pentaxophile wrote:
The softness on the K-5 samples may be a stronger AA filter at work. BUT I am sure the softness would not really translate into prints that have been post processed. Just like the noise on the K-7 would not, up to ISO800 if not beyond in some cases.

Maybe it's better to fully process two or three ISO's and then compare those photos.
It's like you suggest a different sensor so it would behave differently.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
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