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Author Topic: Excited about the Pentax 645D all over again?  (Read 34231 times)
BernardLanguillier
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« Reply #20 on: September 07, 2010, 11:21:47 PM »
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14bit and FP shutter put the Pentax out of my interest. 10K can buy you a Hasselblad H3DII-31 these days. Amazing system with incredible software and lenses.

I can understand FP, sorry but the 14 bits comments doesn't make much sense.

It has been proven many times that the 2 last bits do not contain any information in MF 16 bits files. They do not contribute the least bit to DR whether measured or real world (assuming there is a difference which looks more and more like a myth).

As far as these 2 bodies selling for the same price, you get a lot more with the Pentax if you are an outdoor shooter, the same kind of difference you get between a 1ds3 and a 50D.

Cheers,
Bernard
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LKaven
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« Reply #21 on: September 07, 2010, 11:28:41 PM »
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I couldn't agree with that more ^

14bit and FP shutter put the Pentax out of my interest. 10K can buy you a Hasselblad H3DII-31 these days. Amazing system with incredible software and lenses.
There are no cameras made that put out more than 14 bits of DR that I know of.
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TimG
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« Reply #22 on: September 07, 2010, 11:44:39 PM »
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There are no cameras made that put out more than 14 bits of DR that I know of.

You mean 14 stops of DR, don't you?



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Nick Rains
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« Reply #23 on: September 08, 2010, 03:18:48 AM »
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if I'd need high ISO I'd go Hasselblad or Pentax as this latest Kodak sensor seems to do very, very well at ISO800 and even ISO1600 (which begs the question why the S2 with the same sensor technology looks so aweful at mid range and higher ISO).

Where do you get this idea from? I'm interested as I have been working with the S2 for a while now and at 320 (using LR3) it's very good. 20"x30" prints are totally noiseless. I have not seen the 'Blad to compare though.
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Rob C
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« Reply #24 on: September 08, 2010, 03:31:35 AM »
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(Off Topic)

I agree . . . come in with nuthin', leave with nuthin".

BC



The big difference in attitude comes along with the years. When I started off on my own, I never gave the period ten years ahead a thought; it was all about now. When the pension comes along (if it does) and the bank stops paying interest, capital dwindles, you think of the guy in the pinstripe suit standing at the corner of Sunset and Vine with his hat at his feet, and the placard around his neck, saying: my calculations were wrong.

The arrogance of youth is one of its principle attractions - for the young. Along with its facile fascination with the suicide solution.

;-)

Rob C
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KLaban
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« Reply #25 on: September 08, 2010, 03:59:13 AM »
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Quote
. . .come in with nuthin', leave with nuthin".

Agreed, and the years merely reinforce my attitude.

Most here seem to have well paid day jobs and buy cameras because they want to rather than have to. They are supporting the industry, funding development and making it possible for those who earn a crust with cameras to have a greater choice of equipment.

All of this is relative. "10,000 whatsits" is a comparative bargain, ain't much more than a couple of Nikon and Nikkor impulse buys which in turn is more than enough to buy an M9.

Buy wise...

« Last Edit: September 08, 2010, 04:11:26 AM by KLaban » Logged

ErikKaffehr
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« Reply #26 on: September 08, 2010, 05:44:02 AM »
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Bits and stops are essentially the same. A bit means a factor of two and a stop means a factor of 2.

So, 14 stops is 2^14 that is a range 1 - 16384 and 14 bits is a range from 1 - 16384.

These figures will on the other hand not be achieved, as they are limited by full well capacity, the number of photons a sensel can detect (actually electrons, to be precise) and the readout noise. Typical values may be 50000 for full well capacity and perhaps 15 electrons of readout noise.  These values assumed DR would be around log(50000/15)/log(2), that is around 11.7 stops.

The higher figures given by DxO are possible because of downsampling or better read out electronics.

Much at the noise at low exposures (in the darks) come frome shot noise, variaton in the incident number of photons. Electronics cannot do much about this.

Best regards
Erik
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Doug Peterson
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« Reply #27 on: September 08, 2010, 07:33:57 AM »
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The only thing that would get my heart pounding nowadays would be Hasselblad coming with a CFV39 back with an inner revolving sensor!  
Now, that would be a smart move!
Eduardo

You mean like an Leaf Aptus-II 10R in a V mount which has an internally rotating sensor? You can buy one today :-).

Though its 56 megapixels, not 39 :-/.


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BrendanStewart
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« Reply #28 on: September 08, 2010, 07:56:14 AM »
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There are no cameras made that put out more than 14 bits of DR that I know of.

Well i guess that is marketing mumbo jumbo by Hasselblad then? Maybe i'm like the many sheep before me that look at numbers, 16 vs 14, 16 sounds better to me. 14bit is what Canon's offer. I figured MF has more range than the 35mm 5DMKII's i've been using.

Am i wrong?
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ondebanks
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« Reply #29 on: September 08, 2010, 09:28:09 AM »
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Well i guess that is marketing mumbo jumbo by Hasselblad then? Maybe i'm like the many sheep before me that look at numbers, 16 vs 14, 16 sounds better to me. 14bit is what Canon's offer. I figured MF has more range than the 35mm 5DMKII's i've been using.

Am i wrong?

Yes, unfortunately.

There is a myth of better DR in MF digital. It used be true, a fact; but when belief persists when the fact no longer does, then it becomes a myth.

8 or so years ago when DSLRS had high sensor readnoise (around 20 electrons), in the same ballpark as MFDBs, then it was true that MF digital had a substantial DR advantage.

But it is now a myth, largely because people (and indeed manufacturers' advertising blurbs) only look at one half of the DR equation: full well capacity. MF has larger pixels (for a given total pixel count), so it has larger FWC.

Ever since CMOS replaced CCD for DSLRs, they have been eating into that advantage, by driving down sensor readnoise; currently the best are only 2 or 3 electrons at mid-ISOs. But at mid-ISO you are utilising less of the FWC than at base ISO, so this renders the mid-ISO DR of DSLRs very good but not spectacular (usually 11-and-a-bit stops). At base ISO, you get the complete FWC but countering that, DSLRs still have stubbornly high low-ISO readnoise because the main contributor is the ADC, not the sensor itself. So again you usually get 11-and-a-bit or maybe 12 stops. All told, this means that DSLRs are around par with the MFDBs, which also have 12 +/- a bit stops.

However Nikon seems to have cracked the problem with ADC noise at low ISO in the D3x, and this explains its huge DR score (13.65 stops at base ISO) in the DXO tests.

So if you "figured MF has more range", you have to realise that there is no magic involved in MF digital. It obeys the same rules as 35mm and smaller digital. If or when Kodak and DALSA can get their sensor readnoise down from 11 or 13 electrons (their current best) to 2 or 3 electrons, then MF will regain the upper hand. It certainly can be that low for large CCDs, but it nearly always requires much longer readout times than photographers are likely to put up with. Astronomers are not as fussy about waiting  Wink.
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BartvanderWolf
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« Reply #30 on: September 08, 2010, 09:56:22 AM »
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Ever since CMOS replaced CCD for DSLRs, they have been eating into that advantage, by driving down sensor readnoise; currently the best are only 2 or 3 electrons at mid-ISOs. But at mid-ISO you are utilising less of the FWC than at base ISO, so this renders the mid-ISO DR of DSLRs very good but not spectacular (usually 11-and-a-bit stops). At base ISO, you get the complete FWC but countering that, DSLRs still have stubbornly high low-ISO readnoise because the main contributor is the ADC, not the sensor itself. So again you usually get 11-and-a-bit or maybe 12 stops. All told, this means that DSLRs are around par with the MFDBs, which also have 12 +/- a bit stops.

However Nikon seems to have cracked the problem with ADC noise at low ISO in the D3x, and this explains its huge DR score (13.65 stops at base ISO) in the DXO tests.

So if you "figured MF has more range", you have to realise that there is no magic involved in MF digital. It obeys the same rules as 35mm and smaller digital. If or when Kodak and DALSA can get their sensor readnoise down from 11 or 13 electrons (their current best) to 2 or 3 electrons, then MF will regain the upper hand. It certainly can be that low for large CCDs, but it nearly always requires much longer readout times than photographers are likely to put up with. Astronomers are not as fussy about waiting  Wink.



Well summarized! Another under-utilized feature of CMOS devices is that read-outs are non-destructive. This means that sensels can be read multiple times, even with different gain settings. That offers a lot of additional opportunities to reduce read-noise even further.

One possible reason, besides cost reduction and FPS bragging rights, why manufacturers are slow to offer the choice, is that optical glare will reduce the effective DR delivered to the sensor array to more limited levels (say 9 stops with good coatings and lens shading) than currently already accommodated.

Cheers,
Bart
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BrendanStewart
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« Reply #31 on: September 08, 2010, 11:43:14 AM »
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So if you "figured MF has more range", you have to realise that there is no magic involved in MF digital. It obeys the same rules as 35mm and smaller digital. If or when Kodak and DALSA can get their sensor readnoise down from 11 or 13 electrons (their current best) to 2 or 3 electrons, then MF will regain the upper hand. It certainly can be that low for large CCDs, but it nearly always requires much longer readout times than photographers are likely to put up with. Astronomers are not as fussy about waiting  Wink.


That's great information ondebanks? Do yo have a real name?

While the DR may be the same, i'm quite happy still with leaf shutters and higher resolution. So it's not a total killer for me to find out that it has equal DR to a D3X.  In fact, leaf shutters have changed things for me hugely, especially when using strobes outdoors.

While i don't doubt what you are saying here, it all sounds technical and righteous enough - i have to refute it on some level. That being, i was recently at a friends studio, he had a Leaf Aptus 7 i believe it was, he took a particular shot, and i took the same shot with my 5DMKII with similar settings, and the resulting image was HUGELY different. He had values in shadows that could be restored and some of his highlights were also not pure white.  Meanwhile, the 5DMKII was not even close in being able to compete with that.

Perhaps that leads into the pixel size that you spoke of. Granted a 5DMKII may be no D3X, but it couldn't have all been in my mind.

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peterurban
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« Reply #32 on: September 08, 2010, 12:10:07 PM »
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... I could write for the rest of the evening about all the bells and whistles that every japanese dslr's maker do every 3 years to make those bodies exciting to own. It is a very tough act to follow for the considerable smaller MF manufacturers. ...

Eduardo, people that buy into MF digital do it for the image quality (an some maybe for the extra DOF) and not because they want face detection, direct nonsense print buttons and video games on the back screen of the camera - that's what we have iPhones and iPads for - don't we  (please forgive my flash of sarcasm).

No, people that choose MF digital care about nothing but producing the best possible image quality (within their budget range) period.

Different shooting requirements will always point into different directions for camera solutions ....
- if you need a technical camera (movements) you need a dedicated back to put on it ...
- if you shoot people outside a lot you'll likely need fill flash and should not go without leaf shutters for higher sync speeds...  and so on. Those are all individual requirements and warrant case by case decisions.

Obviously, top-end digital lenses for technical cameras will do better then any SLR based lenses - the exclusion of a mirror box simple allows for a better optical path but agin, that's not in question here.

The question on this threat should be imho is the Pentax 645D the price-breaker that gives us a modern, ergonomic focal plane shutter based system that delivers 40Mpix quality equivalent to it's competition at around $10k?

Or are there any corners cut that lets us end up with a camera system that shows all the (sensor) specs but ultimately can't compete with its (currently) more expensive counterparts on IQ?
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Peter Urban
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Guy Mancuso
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« Reply #33 on: September 08, 2010, 01:30:43 PM »
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Agree Peter. How I view the Pentax is it is just like the ZD with improvements of course but a good entry level cam into the MF world. It's a good beginning but certainly i would not give up my Phase for it and if I was in the market to buy than Hassy or Phase over it because of my needs. I ultimately think SYSTEM and not parts but from a Pro's POV we have to think like that as we have many requirements and for some of us many different types of work that need different functions and parts to support us. Just like the S2 for me there are some holes in these systems via software, tethering and such. But for a lot of folks this may be the ticket to MF so end of day this coming to market maybe a good thing for the industry even for it's competitors. People move up all the time to better systems and once they are in MF it is not easy IQ to get out of it at least for me it is not. No way
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Dave Gurtcheff
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« Reply #34 on: September 08, 2010, 02:33:30 PM »
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Rob: You are absolutely right in my case. I don't need a MF digital camera. I am not a pro. But I sell enough of my work to support my habit, and then some. When I shot 35mm film and made 16"x20"s in my darkroom, I also shot 645 and 6x7 and the resulting quality differences were striking. I am asuming the quality diffences in digital to be similar (I use 1DSIII and A900 equipment). Regarding how we spend our money....we are all different. My Dad died when I was three. I went to Drexel University for 12 years at night to earn BS and MS degrees. My wife and I are proud of the fact that we raised three sons, and financed 7 college degrees for our family. I am 73 years old....guess what? It's my time to buy my toys.  Roll Eyes
Best to all....
Dave
www.modernpictorials.com
However good the camera might be, there is a definite stumbling block at that price (10,000 whatsits).

Frankly, for the money, I would rather have an M9 and that's still out of reach. Now don't misunderstand: as with Mercedes, BMW, small boats et al I can go write a good cheque. But that does not mean that I can really afford it! There is a wealth of difference (NPI) between the two propositions - the doing and the should I. In short, if it's pro, then of course you should do it; if for fun, then perhaps a dose of reality is what the doc should order.

No desire to spoil anyone's breakfast with this, but I do think that many just throw money away - even I have done so, but that's an age thing: the first one, concerning my 'blads, being a male menopause one; the later ones just desperation, buying solutions that really have to come from the mind instead. I was watching Bloomberg the other day, and somebody came up with a novel soundbite (novel to me) when he said that spending money should be as easy as running barbed wire through your fingers. I thought about that, and wish he'd said it a few years ago.

You really can learn from tv after all.

Rob C
Rob You are absolutely right in my case. I don't need a MF digital
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LKaven
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« Reply #35 on: September 08, 2010, 04:52:18 PM »
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You mean 14 stops of DR, don't you?
Since the sensors are linear, then in RAW output, 14 stops ~= 14 bits.
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BernardLanguillier
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« Reply #36 on: September 08, 2010, 04:54:02 PM »
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Agree Peter. How I view the Pentax is it is just like the ZD with improvements of course but a good entry level cam into the MF world. It's a good beginning but certainly i would not give up my Phase for it and if I was in the market to buy than Hassy or Phase over it because of my needs. I ultimately think SYSTEM and not parts but from a Pro's POV we have to think like that as we have many requirements and for some of us many different types of work that need different functions and parts to support us. Just like the S2 for me there are some holes in these systems via software, tethering and such. But for a lot of folks this may be the ticket to MF so end of day this coming to market maybe a good thing for the industry even for it's competitors. People move up all the time to better systems and once they are in MF it is not easy IQ to get out of it at least for me it is not. No way

Sure, the Pentax is not a solution for you if you need thethering, leaf shutters, to be able to use the back on a view camera or T/S lenses.

Other than that it appears to be to be equal or superior to anything else 40MP class MF out there, and that would include image quality. There is a huge difference between Mamiya and Pentax here, Pentax has a lot of experience in digital (read tens of M$ of investement over 10+ years and very skilled engineers inhouse in a job market place where there are many more skilled engineers) and is able to amortize their digital research over many more bodies. They are also part of the powerful Hoya group known for its leadinf research in optics. If the 645D proves to be a commercial succes (they are off with a very good start), Hoya will GO more investements targetting the MF market.

All that being considered, It would in fact be surprising if the MF copanes were able to keep up with them in image quality giving the same sensor is used.

Cheers,
Bernard
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LKaven
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« Reply #37 on: September 08, 2010, 05:02:26 PM »
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While i don't doubt what you are saying here, it all sounds technical and righteous enough - i have to refute it on some level. That being, i was recently at a friends studio, he had a Leaf Aptus 7 i believe it was, he took a particular shot, and i took the same shot with my 5DMKII with similar settings, and the resulting image was HUGELY different. He had values in shadows that could be restored and some of his highlights were also not pure white.  Meanwhile, the 5DMKII was not even close in being able to compete with that.

Perhaps that leads into the pixel size that you spoke of. Granted a 5DMKII may be no D3X, but it couldn't have all been in my mind.

The 5DII is rather limited in DR, having between 1-2 stops less than the D3x, due especially to pattern noise in the shadows.  It's also older technology, about four years old now.
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JonathanBenoit
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« Reply #38 on: September 08, 2010, 05:10:21 PM »
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Other than that it appears to be to be equal or superior to anything else 40MP class MF out there, and that would include image quality. There is a huge difference between Mamiya and Pentax here, Pentax has a lot of experience in digital (read tens of M$ of investement over 10+ years and very skilled engineers inhouse in a job market place where there are many more skilled engineers) and is able to amortize their digital research over many more bodies. They are also part of the powerful Hoya group known for its leadinf research in optics. If the 645D proves to be a commercial succes (they are off with a very good start), Hoya will GO more investements targetting the MF market.

All that being considered, It would in fact be surprising if the MF copanes were able to keep up with them in image quality giving the same sensor is used.

Cheers,
Bernard


Wow. It's a little premature to make any of these claims.
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Nick Rains
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« Reply #39 on: September 08, 2010, 05:15:41 PM »
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The D3X is an amazing bit of gear and IMHO, hits a sweetspot of price vs performance, much like the 5D2, just further up the scale. If I wasn't committed to Canon for this style of camera I'd have one in a flash.

I agree anecdotally about the DR being excellent, not having measured it on a test bench, but I do NOT see more DR than MFDBs. Visually on a monitor, and in 20"x30" prints, they are much the same. I'd even go so far as to suspect Nikon of some clever 'under the hood' NR since the really deep shadow textures have a subtle plasticity to them that the S2 does not.

The only samples I have seen from the Pentax were underwhelming but I'm keen to see more. I used to use the classic Pentax67 and the lenses were simply stunning so that won't be a limiting factor.
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