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Author Topic: Fat Pixels  (Read 5158 times)

ron lacy

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Fat Pixels
« on: January 12, 2018, 05:04:04 PM »

I am not very knowledgable about digital backs but have always lusted for one because of the quality images I see posted here and elsewhere.  I have been a hobbyist for 45 years and have shot Nikon and Fuji digital for the past 15 years.  However, as I said earlier I really have a desire for a MF camera with a digital back.  I continue to read about the "fat pixel" backs.  Can someone explain to me what that means and what advantage would that have to a landscape photographer like me?  I hear this comment about the Phase One P30+.  I am currently looking at one and am close to making an offer but really want to understand what the fat pixel thing in about and why that might be important to me.

Any info you can share would be appreciated.

Thanks
Ron
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BernardLanguillier

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Re: Fat Pixels
« Reply #1 on: January 12, 2018, 05:27:59 PM »

Frankly, in my view you’d be better off with a a7rIII or D850.

If you really want to go MF at least go for a P45+ with a decently sized sensor, although Erik may talk you out or it also... ;)

Cheers,
Bernard

douglevy

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Re: Fat Pixels
« Reply #2 on: January 12, 2018, 05:44:56 PM »

Agree with Bernard. I've shot those p+ backs, and owned a D810 and now 850. The 850 beats any back I've used from the P+ generation almost across the board. The lenses are obvs better with the phase/hassy and leaf shutters, but at the moment I'd take my 850 over anything but the IQ/Credo series backs (and I own a Credo 60).

siddhaarta

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Re: Fat Pixels
« Reply #3 on: January 12, 2018, 08:35:23 PM »

There is a long thread here:
 
Fat Pixels

Worthwhile reading and it should answer your questions or at least increase your confusion :)

In general, it refers to pixel size as apposed to pixel count. Fat Pixel sensors would be e.g. the P25+ or Hasselblad CFV-16 with 9 micron. The pixels of the P30+ with 6.8 micron are not that "fat" (even less the P45+ or P65+ with 6 micron). All these sensors are quite older CCD types and have some disadvantages as compared to newer CMOS sensors with much more (and smaller) pixels. Whether these fat pixels with old sensor tech render better than smaller ones with newer sensor tech is an interesting discussion :). They are certainly "easier" for older lenses.

Only thing I can say is that I have a P25 back on my Contax 645 and would not part from it, because it gives me a special look ... and yes I have a modern CMOS sensor on my Hasselblad X1D.
« Last Edit: January 12, 2018, 09:18:02 PM by siddhaarta »
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Hank Keeton

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Re: Fat Pixels
« Reply #4 on: January 12, 2018, 09:27:39 PM »

If you really want the "skinny" on "fat" pixels...visit Roger Clark's website at www.ClarkVision.com.

After your brain fatigues from digesting all that info...you'll be able to rest a bit...re-group...and make a "well-nourished" decision!

Enjoy!

Hank
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MichaelEzra

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Re: Fat Pixels
« Reply #5 on: January 12, 2018, 10:04:17 PM »

My old 22 MP Mamiya ZD produces files significantly sharper than 645Z or D800e, at the pixel level. Sensor is larger than 645z and so are the pixels.
Must be the fat pixels, or that and lenses, although Pentax 645 primes are excellent. These pixels also scale well, I printed 60" wide from cropped ZD file (with very careful enlarging and sharpening) and it looks amazing.
However, I haven't used ZD in a while... thought of selling it, but never got to it.. and so it sits with its fat pixels looking back at me:)
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ErikKaffehr

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Re: Fat Pixels
« Reply #6 on: January 12, 2018, 11:10:58 PM »

Hi,

Early MFDs had large pixels, like nine microns. That meant that they operated at low frequencies, so they delivered very high edge contrast at the pixel level. Sharpness is usually checked at actual pixels, and those fat pixels looked really good at actual pixels.

Now, modern cameras are around 4.5 micron pitch. That corresponds to something like 110 lp/mm and few lenses will be able to deliver very high contrast at 110 lp/mm, so the images will look a bit soft at actual pixels. But, using the late generation of images at actual pixels would mean twice the magnification.

If you make C-size or A2-size prints, 16-25MP are quite enough to produce an excellent print. So the fat pixel backs would produce very nice prints.

The major downside of fat pixels is that fat pixel backs are very sensitive to moiré. Stopping down increases diffraction thus eliminating moiré (and reducing sharpness).

With my P45+ back having 6.8 micron pixels I need to stop down to f/16 to reduce moiré. With 9 microns you would need f/22 and with 4.5 microns f/11. These apertures can still yield traces of moiré.

Just to say, when I made a few comparisons when I got my 39MP P45+ and I didn't see a meaningful difference between that and my 24 MP system at 16"x23" (A2) print size. But, any such comparison depends on sharpening. You can make very nice 30"x40" images from 24 MP.

Best regards
Erik


I am not very knowledgable about digital backs but have always lusted for one because of the quality images I see posted here and elsewhere.  I have been a hobbyist for 45 years and have shot Nikon and Fuji digital for the past 15 years.  However, as I said earlier I really have a desire for a MF camera with a digital back.  I continue to read about the "fat pixel" backs.  Can someone explain to me what that means and what advantage would that have to a landscape photographer like me?  I hear this comment about the Phase One P30+.  I am currently looking at one and am close to making an offer but really want to understand what the fat pixel thing in about and why that might be important to me.

Any info you can share would be appreciated.

Thanks
Ron
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Erik Kaffehr
 

landscapephoto

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Re: Fat Pixels
« Reply #7 on: January 13, 2018, 07:46:31 AM »

There is something about the colours of the backs of that era that I do not see in modern backs. Interestingly, some SLRs of that era also had these colours, so it was not exclusive to MF backs.

The colours of that era look more intense to my eyes, but it cannot be corrected by simply increasing saturation or vibrancy on today's cameras. Skin tones on fair skinned models also look different, the skin looks younger.

The colours of modern cameras are probably a bit more accurate, though.
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ErikKaffehr

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Re: Fat Pixels
« Reply #8 on: January 13, 2018, 08:23:48 AM »

Hi,

Many of the older backs had sensor made by Kodak with Kodak's colour filter array designs. Phase One used Kodak sensors until the P65+, that used DALSA. Leica M8-M9 also used Kodak CCD and so did Pentax 645D.

A very large part of colour rendition depends on colour profiles, but some properties may depend on CFA design.

It may be possible that a sensor would yield strong greens but not being able to separate different greens like clorophyll A and clorophyll B. So, it may yield a very pleasant green but entirely miss that the original greens are quite different.

Best regards
Erik



There is something about the colours of the backs of that era that I do not see in modern backs. Interestingly, some SLRs of that era also had these colours, so it was not exclusive to MF backs.

The colours of that era look more intense to my eyes, but it cannot be corrected by simply increasing saturation or vibrancy on today's cameras. Skin tones on fair skinned models also look different, the skin looks younger.

The colours of modern cameras are probably a bit more accurate, though.
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Erik Kaffehr
 

eronald

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Re: Fat Pixels
« Reply #9 on: January 13, 2018, 11:03:39 AM »

The big 22 MP sensors are the last ones with "fat pixels" AFAIK.
They moiré like crazy - low fill factor.

Edmund



Hi,

Many of the older backs had sensor made by Kodak with Kodak's colour filter array designs. Phase One used Kodak sensors until the P65+, that used DALSA. Leica M8-M9 also used Kodak CCD and so did Pentax 645D.

A very large part of colour rendition depends on colour profiles, but some properties may depend on CFA design.

It may be possible that a sensor would yield strong greens but not being able to separate different greens like clorophyll A and clorophyll B. So, it may yield a very pleasant green but entirely miss that the original greens are quite different.

Best regards
Erik
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KLaban

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Re: Fat Pixels
« Reply #10 on: January 13, 2018, 12:34:48 PM »

As much as I loved my "fat pixel" 22MP back I wouldn't have used it if my principal client had been Harris Tweed.

;-)
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ron lacy

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Re: Fat Pixels
« Reply #11 on: January 13, 2018, 11:37:24 PM »

Well, thanks to all for replying and giving information and their point of view.  I have learned a lot from reading the reply and checking some of the websites mentioned.  I am a lot more knowledgeable now about fat pixels.  i am not sure what i am going to do with all of this information, but I at least I know more know.  I guess I'll need to think about everything that has been mentioned and see what makes sense to me.

Thanks again
Ron
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ron lacy

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Re: Fat Pixels
« Reply #12 on: January 13, 2018, 11:39:50 PM »

If you really want the "skinny" on "fat" pixels...visit Roger Clark's website at www.ClarkVision.com.

After your brain fatigues from digesting all that info...you'll be able to rest a bit...re-group...and make a "well-nourished" decision!

Enjoy!

Hank

Hank, thanks for the reply.  You are right.  After reading some of Roger Clark's website my head hurts.  Don't know if I understand everything he talks about, but it is an interesting website.

Ron
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DezFoto

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Re: Fat Pixels
« Reply #13 on: January 18, 2018, 03:04:02 PM »

The "Fat Pixel" backs also don't have microlenses, which I think increases the pixel-level contrast since there's less cross-talk between pixels.
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ben730

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Re: Fat Pixels
« Reply #14 on: January 19, 2018, 11:31:01 AM »

Hi
For those who are interested I uploaded three RAW pictures. One with the fat pixel P25+ (Sensor by Kodak, CCD), one with the P40+ (Sensor by Dalsa, CCD) and an other with IQ150 (Sensor by Sony, CMOS).
Camera was Cambo WRS with 32HR, 5mm shift down, no CF, no LCC, F11.

The P25+ is still a great back. I like those files and I like them more than my D810 files.

https://www.dropbox.com/sh/ckfqdv2no2ys7k6/AAAaygIOAdV8nfC69770hDN1a?dl=0

Regards,
Ben
« Last Edit: January 20, 2018, 08:31:11 AM by ben730 »
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bcooter

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Re: Fat Pixels
« Reply #15 on: January 19, 2018, 06:01:47 PM »

I am not very knowledgable about digital backs but have always lusted for one because of the quality images I see posted here
snip
Thanks
Ron

Use what you want, but don't believe everyone, even me.  I've used and still do use the p30+

Downside, 800 iso is tops (never need more),

upside the look and the back never breaks.



It's an interesting back,  better than my Leica S2 with the contax 645 and the files are robust.

IMO

BC
« Last Edit: January 20, 2018, 11:51:51 AM by bcooter »
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ben730

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Re: Fat Pixels
« Reply #16 on: January 19, 2018, 06:46:43 PM »

Use what you want, but don't believe everyone, even me.  I've used and still do use the p30+

Downside, 800 iso is tops (never need more),

upside the look and never breaks.



to see larger option click (on image) and open in new window.  Then double tap the image.

It's much better than my Leica S2.

Camera Contax 645

IMO

BC


BC, the P30+ is not a fat pixel back, although your models are skinny. ;)
I'm sorry.

Regards,
Ben
« Last Edit: January 19, 2018, 06:55:54 PM by ben730 »
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bcooter

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Re: Fat Pixels
« Reply #17 on: January 23, 2018, 07:16:52 PM »


BC, the P30+ is not a fat pixel back, although your models are skinny. ;)
I'm sorry.

Regards,
Ben

I think sometimes we concern ourselves more with the technical specs of a camera than we do who is viewing the image.

This article is more about motion than still photography, but has a some crossover.

I'd look at part two rather than part one as part two has more real life information.

http://yedlin.net/ResDemo/

I select a camera for a lot of reasons, some not always logical, but that's a matter of opinion, not always fact.

These are "fat" pixel images  these from my p21+ at 18 native mpx,


This from a 1dx 1 also at 18 native mpx.


Obviously different genres, so different cameras, but the mlx never concerned me, getting the image did.
(these are way knocked down jpegs, so they're not meant for pixel comparison but they worked, we're approved, life goes on).

Why these cameras/backs?  Because the p21+ shoots at the same speed on the contax as quickly as film did, the 1dx is rugged, takes a beating and focuses very accurately.

Actually the bottom shot is done one handed while I bounced around on the back of the lead ATV at about 35 to 40mph.

Would they make a difference at 100mpx?  Don't know but I'll use either of the cameras without blinking.

But I'd always test before I would rely on camera specs.  My RED Ones are reported at around 12bit files and compared to a still camera advertised as 14 bit the ol' RED one has more lattitude.   

But as they say horses for courses, though I say if it ain't broke, don't worry about it.

IMO

BC
« Last Edit: January 23, 2018, 07:20:40 PM by bcooter »
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ErikKaffehr

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Re: Fat Pixels
« Reply #18 on: January 23, 2018, 10:06:08 PM »

Hi BC,

A point that I would make that any camera intended for motion would have an OLP filter matching the pixels. I would also guess that the RED you use does not have fat pixels, like 9 micron. So, it is not the number of pixels but about rendition of detail. Motion folks don't like moiré, I have been told.

I mostly print at 16"x23", that is the European A2 format. At that size, I found that something like 12-16 MP is all I need, mostly. It did happen that I preferred 16MP (APS-C) to 24MP (FF) at times, as things worked out better with the smaller sensor. More accurate focus and better high ISO capability and being able to use a better lens.

But, at times I am also making larger prints. In my case mostly 27"x39" and in that case I would feel more MP can be beneficial.

While I was shooting P45+, I never felt that it did not have all the MPs I needed. But it didn't mix well with my way of shooting. The reason I think so is that so few P45+ images made it the wall.

Best regards
Erik
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Chris Livsey

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Re: Fat Pixels
« Reply #19 on: January 24, 2018, 02:38:26 AM »

I think sometimes we concern ourselves more with the technical specs of a camera than we do who is viewing the image.

I select a camera for a lot of reasons, some not always logical, but that's a matter of opinion, not always fact.

These are "fat" pixel images  these from my p21+ at 18 native mpx,

BC

I was rather hoping for some of those BC M8 images  ;D, mine is back at Leica for a service, they did say they would upgrade it forever, let's see. It still has lovely colour and B/W, use it within its limitations and all is good. There's a reason they still sell at £1,000.
Fat pixel backs are a bargain now for their output. IMHO  8)
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