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03-08-2017, 06:22 PM   #31
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Btw I converted my 50-135mm to screwdrive this evening and then tried it on K-1. Fantastic. It seems to zoom a little quicker than SDM and it isn't that loud at all.

03-09-2017, 01:57 AM   #32
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QuoteOriginally posted by Rondec Quote
But I still think the question is what happens when you print at a given size or view at a given size .
Well, sizing doesn't have anything to do with it, Rondec, because the noise and dynamic range are the same whether they're from the cropped portion of a frame or outside it. A RAW file is a RAW file, and the pixels don't know where they are on the sensor.

As for resolution, if the output device is, say, 150 dpi, if you resize there is no difference in a 5x7 print or a computer monitor.

You would need to go to A3 to see an effect.

If you resize down to 8Mp, there is no change in noise or dynamic range, either. That's impossible.

There are folks around here who are uncomfortable with postprocessing. But to the rest of us, that's part and parcel of photography.

So if you're not just resizing, you're also doing some sort of postprocessing that includes downsampling, in poor light conditions you'd expect to see about a stop's difference between your K-5 and K-1. Alright, it destroys details too, but the idea is that details aren't random, noise is, and so to a point, averaging is desirable.

You can see from my night concert shot above, I think it was worth my money to chase that marginal improvement. And you obviously feel the same about your very delicate landscapes. If there's anyone we should crowdsource a 645Z for, it's you, Vincent!

Last edited by clackers; 03-09-2017 at 02:05 AM.
03-09-2017, 02:13 AM   #33
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QuoteOriginally posted by mee Quote
Btw I converted my 50-135mm to screwdrive this evening and then tried it on K-1. Fantastic. It seems to zoom a little quicker than SDM and it isn't that loud at all.
Sure, it speeds up when you convert it, Mee. I have so many screwdrive lenses I'm used to the noise. It's got such terrific IQ I don't mind using it in crop mode on the K-1 at all:

03-09-2017, 02:25 AM   #34
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QuoteOriginally posted by clackers Quote

If you resize down to 8Mp, there is no change in noise or dynamic range, either. That's impossible.
Careful. It isn't that straightforward, really. If you resize, either up or down, noise matters, especially when you do the final output sharpening, which is required in all workflows. The different algorithms used to resize, sharpen (and there is a choice here) as well as the noise processing whilst sharpening, all effect the final output, be it screen or print. So saying there is no change in noise might be a little misleading. Just adding my pennies worth ...

03-09-2017, 03:00 AM   #35
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QuoteOriginally posted by BarryE Quote
Careful. It isn't that straightforward, really. If you resize, either up or down, noise matters, especially when you do the final output sharpening, which is required in all workflows. The different algorithms used to resize, sharpen (and there is a choice here) as well as the noise processing whilst sharpening, all effect the final output, be it screen or print. So saying there is no change in noise might be a little misleading. Just adding my pennies worth ...
A resize cannot effect noise, Barry. You are simply dropping three out of every four pixels, for example, no matter what they are, leaving the fourth intact. If every tenth pixel was noise, it still is in the output.

Downsampling is required to reduce that ratio. There you are replacing all four pixels with a single averaged value.

That is why skin textures become plastic when pushing the noise reduction slider. You are averaging out the details you want to keep.

The lesson? Go for the cleanest possible image with the best performing sensor in the first place, instead of relying on post processing.
03-09-2017, 03:28 AM - 1 Like   #36
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QuoteOriginally posted by clackers Quote
A resize cannot effect noise, Barry. You are simply dropping three out of every four pixels, for example, no matter what they are, leaving the fourth intact. If every tenth pixel was noise, it still is in the output.

Downsampling is required to reduce that ratio. There you are replacing all four pixels with a single averaged value.

That is why skin textures become plastic when pushing the noise reduction slider. You are averaging out the details you want to keep.

The lesson? Go for the cleanest possible image with the best performing sensor in the first place, instead of relying on post processing.
Agreed Clackers, go for the cleanest image to start with.

My point, probably poorly made, is that the initial noisy image, when reduced, will have a proportion of pixels discarded. The remaining images will still have noise. Then depending on the image, subsequent processing, particularly at the output sharpening stage, can make an original noisy image look much better. It is harder to achieve this when interpolating an image. Been working with images in PS and Illustrator for years since I was employed to do this stuff. Guess we both know what we're trying to say, only I sometimes just type and don't think too hard ;-)
03-09-2017, 05:05 AM   #37
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I don't understand the technical arguments but I had the K3 and the K5 before that.

Where the K3 would start to make a given amount of visible noise at say ISO 500 (as seen in Lightroom etc at 1:1) the K1 makes a similar noise at about ISO 2000. So the low light performance of the K1 is a lot better. IOW, one can shoot at higher ISOs, which is relevant to me because I shoot mostly in the TAV mode.
03-09-2017, 05:24 AM   #38
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QuoteOriginally posted by clackers Quote
A resize cannot effect noise, Barry. You are simply dropping three out of every four pixels, for example, no matter what they are, leaving the fourth intact. If every tenth pixel was noise, it still is in the output.
No you are not, no one resizes an image using some sort of skipping algorithm. Not even computer games resizing their texture maps in real time does that since the result is so utterly bad. That is simple not how you resize an image. Maybe MS paint in windows 3.1 does it like that, but that is about it.

03-09-2017, 06:52 AM   #39
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I have compared my K5IIs shots to my K1 Crop Mode shots and the K5IIs is the clear winner in low light noise. I think this posted by Clackers is very informative.... Pentax K-1 vs Pentax K-5 IIs

If I had bought the K1 for better low light shooting and less noise, I would be highly disappointed. My desire was for much better AF in all light, good or bad, and the K1 has certainly delivered in that respect, and made a huge difference in the number of keepers and the ability to get shots fast and accurate. A birdie will not sit and pose while my Bigma spends five minutes hunting for focus. On the K1 there is zero hunting, just point, half press and snap. No other Pentax I have owned even comes close to this action.

My personal dream camera...a K5IIs with the K1 AF system. It would be a killer for wildlife shooting for me!

As for noise....photographers obsess about noise, even when it is ridiculously low. Old Granny that views our shots is more interested in content and the quality of the subject/mood/story told of the shot. What it says or doesn't say.
Noise, within reasonable limits, is not much of a factor to Old Granny.

Squirrels will pose for as long as it take to get a shot of their handsomeness. They will even take a nap while the K5IIs and Bigma go on a hunting trip to find focus...

K5IIs "Wake me when it's over."


Birdies...not so much....



K1 "I'll give you two seconds with your K1/Bigma to see under my wings....after that I'll find me a Nikon shooter!"




K1 AF...works for me!

Regards!

---------- Post added 03-09-17 at 07:55 AM ----------

QuoteOriginally posted by clackers Quote
Sure, it speeds up when you convert it, Mee. I have so many screwdrive lenses I'm used to the noise. It's got such terrific IQ I don't mind using it in crop mode on the K-1 at all:
That is a really nice shot Clackers! I wish I had known I could convert my 50-135 before I sold it. One of the best lenses I have ever owned, just terrific!
03-09-2017, 08:10 AM   #40
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QuoteOriginally posted by Rupert Quote
I have compared my K5IIs shots to my K1 Crop Mode shots and the K5IIs is the clear winner in low light noise.
That is surprising, and not in line with DXOmark.The K-1 in crop mode should be pretty much equal too K5II, with the K-1 having the edge below iso 1600 and the K5II marginally better at higher iso due to the K5II “cheating” with noise reduction on raw files.

But that is in crop mode, if you use the entire K-1 sensor it will outperform the K5II.
03-09-2017, 08:34 AM   #41
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QuoteOriginally posted by Gimbal Quote
That is surprising, and not in line with DXOmark.The K-1 in crop mode should be pretty much equal too K5II, with the K-1 having the edge below iso 1600 and the K5II marginally better at higher iso due to the K5II “cheating” with noise reduction on raw files.

But that is in crop mode, if you use the entire K-1 sensor it will outperform the K5II.
Yes, I was referring to the Crop Mode....different story on FF mode, and not comparable with the K5IIs. My finding was based on an all day study of my shots from both cameras and my memory of the K5 processing and end results.
It wasn't scientific...I'm a damn plumber, not a scientist or pixel peepin' expert!
The K1 is not bad, I didn't mean to imply that, but I do think the K5IIs is better than the K1 Crop Mode...for whatever reasons, I am not certain.

The much, much, superior AF of the K1 offsets any advantage the K5IIs has...or doesn't have.... by a huge margin.

An example...of many instances....I was sitting at my desk and peeked out the windows to see this little girlie in the cloudy afternoon light. Having my K1 & Bigma next to me on my desk, and knowing she would be gone as fast as she came...was there time to pick it up, zoom in, focus and snap? With the K5IIs I would not have likely wasted my time. Hunting could last forever...
But...with the K1 as soon as I zoomed in and half pressed the focus was instant, the Crop Frame lit up and beeped and I snapped. This is a huge difference and results in many more keepers. Gotta love it!



I am currently looking for another K5IIs...I need a backup.....and what could be better!

Regards!
03-09-2017, 03:42 PM   #42
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QuoteOriginally posted by Gimbal Quote
No you are not, no one resizes an image using some sort of skipping algorithm. Not even computer games resizing their texture maps in real time does that since the result is so utterly bad. That is simple not how you resize an image. Maybe MS paint in windows 3.1 does it like that, but that is about it.
Well, you're quite wrong again, Gimbal ....

"When changing the size of an image in Photoshop, there's really two ways to go about it. You can either resize the image, or you can resample it. A lot of people use the terms resizing and resampling as if they mean the same thing, but they don't. There's an important difference between the two."

That's from here ... Image Resizing vs Resampling In Photoshop Explained

Adobe even post a video about this from Lynda.com ... Understanding Resize vs. Resample
03-09-2017, 03:51 PM   #43
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QuoteOriginally posted by peterh337 Quote
I don't understand the technical arguments but I had the K3 and the K5 before that.
Best not to mistake those two for each other, Peter.

They don't have the same pixel sizes ... more are crammed into the K-3's sensor.

As a result, their RAW performance is different ... the K-5 has consistently between 2-3 dB better SNR ratio than the K-3, even though it's an older camera.

The reason we mentioned the K-5 is that it shares the K-1's pixels.
03-09-2017, 11:49 PM   #44
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QuoteOriginally posted by clackers Quote
A resize cannot effect noise, Barry. You are simply dropping three out of every four pixels, for example, no matter what they are, leaving the fourth intact. If every tenth pixel was noise, it still is in the output.
QuoteOriginally posted by clackers Quote
Originally posted by Gimbal
No you are not, no one resizes an image using some sort of skipping algorithm. Not even computer games resizing their texture maps in real time does that since the result is so utterly bad. That is simple not how you resize an image. Maybe MS paint in windows 3.1 does it like that, but that is about it.
Well, you're quite wrong again, Gimbal ....

"When changing the size of an image in Photoshop, there's really two ways to go about it. You can either resize the image, or you can resample it. A lot of people use the terms resizing and resampling as if they mean the same thing, but they don't. There's an important difference between the two."

That's from here ... Image Resizing vs Resampling In Photoshop Explained

Adobe even post a video about this from Lynda.com ... Understanding Resize vs. Resample
I'm not sure what in your reference you think supports your original statement about resizing via simply dropping pixels? Can you be more explicit?
03-10-2017, 02:37 AM - 1 Like   #45
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Do we have to get hung up about all this. Most of us know that adding and removing pixels via any of the resampling/interpolation algorithms changes the image. Processing can then correct this, somewhat. This is why the adding/removing pixels is done at the start of a workflow. Just changing the the image so it will print differently changes nothing - no pixels are harmed in this process. We know this.

Noise is noise. It is worked out of an image in many ways via intelligent processing - not just sliding a slider here and there. Best not to get it in the first place, but it is often overrated. (Noise can be, however, very effectively used to good effect.) Often noise is the result of high ISO being used - high ISO kills the dynamic range. This personally is why I don't like high ISO, not noise, but what it does to the dynamic range. DR can be carefully eased back into an image with curves and masks etc, but it is less than idea.

Get it right in camera, wherever possible, then process the problems away where possible.

Keeping noise down generally - in forums too - is a good idea ;-)
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