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Author Topic: Any disadvantages to the Mark II over 1Ds  (Read 7408 times)
Lin Evans
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« on: May 22, 2004, 12:39:32 PM »
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[font color=\'#000000\']The "disadvantages," if one could really call it that, are that the 1D Mark II has eight megapixels of photosites and the 1DS has 11. The other "disadvantage," but only to the landscape or architectural shooter is that the 1D Mark II has a 1.3x reduced field of view.

On the other hand, the Mark II shoots 8 plus frame per second, has a huge buffer, has greater dynamic range, and looking at the 1.3x reduced field of view from the wildlife or sports photographer's perspective has the 30 percent telephoto "boost" effect.

Both will autofocus reliably at F8.....

Lin[/font]
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Bobtrips
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« Reply #1 on: May 22, 2004, 08:43:26 PM »
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[font color=\'#000000\']Having spent a bit of time in India (while carrying a lot of gear) I can assure you that theft is not a big problem.  And the thieves everywhere steal what is made available to them, they don't check the model number....[/font]
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Ray
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« Reply #2 on: May 25, 2004, 05:54:41 PM »
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[font color=\'#000000\']This means that at least in theory a manufacturer could design a lens with a variable aperture which could shift during the exposure and tap the "potential" for much greater dynamic range latent in the sensor.[/font]
[font color=\'#000000\']Lin,
Can you elaborate on this! Seems to me an aperture that varies during the exposure will simply give you one average exposure and solve nothing with regard to dynamic range. You need at least two separate exposures (I guess this is what you meant).

Two exposures with different f stops will need software similar to Helicon Focus to combine the different DoFs and I see that as problematical since parts of the two images might consist of a well exposed out-of-focus patch which has to be merged with a severely underexposed in-focus patch also deficient in detail for different reasons.

Two exposures with different shutter speeds is the usual approach (or 3 with autobracketing), but requires the subject to be static.

Those who own good RAW conversion software, such as Capture One or Adobe Camera Raw (V.2 or later) can get (roughly) a couple of stops of extra dynamic range out of a single exposure using the following procedure.

(1) Overexpose the image by one stop.

(2) Use exposure compensation during conversion to recover highlight detail.

(3) Do a second conversion but this time move EC the opposite direction, say +3 stops, to create an image with maximum detail in the shadows but completely blown out highlights. (It's probably advisable to move the NR and Luminance Smoothing controls to their maximum also.)

(4) Combine the two images with a 'digital blending' technique. Michael has a tutorial on this.[/font]
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Ray
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« Reply #3 on: May 25, 2004, 09:34:56 PM »
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[font color=\'#000000\']For example, it "could" be that the processor is dumped between exposures to a buffer then later combined but I'm suspicious that it may be done differently.[/font]
[font color=\'#000000\']Lin,
However it's done, it's clear that each photodetector can only hold so many electrons. Once the 'wells' are full, they're full. No more exposures can be made without clearing the charge.

The multiple exposures possible with your S7000Z must be transferred to some sort of buffer, I would imagine. But the question does arise, how fast can the charge be cleared and the sensor reset for another exposure? If it's virtually instantaneous, then there is a clear advantage over autobracketing. For example, if you need 1/30th sec exposure for the shadows in a contrasty scene, which represents say a 3 stop overexposure with regard to the highlights, then the other exposure need be only 1/250th (call it 1/240th for simplification). The combined exposure of a 30th plus a 240th is 9/240ths or approx 1/26th sec. With Canon's Image Stabilisation one could probably get some reasonably sharp hand-held shot at this shutter speed, and if not then just increase the ISO.

Also, combining RAW images in camera should potentially produce better results than digitally blending converted TIFs in PS. I'm all in favour of such a development. I live in a place with lots of sunshine and dark forests. I'm constantly battling with dynamic range issues.[/font]
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didger
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« Reply #4 on: May 26, 2004, 05:34:28 AM »
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[font color=\'#000000\']
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But bracketing with multiple exposures and blending the exposures must, by default, mean that the sensor has the latitude of "holding" the full dynamic range you are able to achieve with the blend of two or more exposures.
Huh?Huh  The reason you bracket is precisely because the sensor DOESN'T have the capacity to hold the full dynamic range.  You overexpose and let the bright parts clip on one shot and you underexpose and let the shadows be black on the other shot and you blend to give you the best combination.

As for doing this all automatically in the camera; maybe as a gimmick for consumer cameras this would be better than nothing to increase dynamic range, but all this processing to create and blend two exposures would have to take some time and during that time camera motion would be even more critical than for normal single exposure shooting.

As for a previous comment that this automatic in camera double exposure and blending being potentially superior to bracketing and saving both raw images for later blending; NO WAY!  Even without the obvious problem that this procedure would have to take some time, and thus be even more sensitive to camera motion, there's also the problem that you have no good visual feedback to see if it really worked right; just a littly tiny LCD camera display.  Blending two images in Photoshop gives you lots of options for exactly how to do the blend and thus getting the best possible blend and you can see exactly what you have for each trial.

In any case 1d and 1ds are both pro cameras and fortunately not burdened with a kluge like automatic in camera double exposure and blending.

Fuji Finepix technology increases dynamic range by having a low sensitivity sensor and a high sensitivity sensor for each pixel location, but for some reason this has not yet been implemented for any pro camera.  Probably doesn't actually work as well as the hype would lead you to believe.[/font]
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Lin Evans
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« Reply #5 on: May 26, 2004, 07:56:18 PM »
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[font color=\'#000000\']Hi Ray,

It "appears" to simply slow to the rate you have set manually and keep chugging. I'm not sure if there are any statistics about this available - nothing in the manual.

I suspect it does much the same if you were shooting in aperture priority mode or auto.

Best regards,[/font]
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Lin
sophos
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« Reply #6 on: May 31, 2004, 01:03:52 AM »
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[font color=\'#000000\']This might be taking the topic even further afield.

If we invented a sensor with an A/D converter for each pixel, and monitored in real time the rate at which each pixel gathered light during the exposure, then it seems like we could select when to grab the intensity of each pixel during the exposure.  We could grab the bright values sooner and the dark values later.  Effectively, we would be exposing for the rate at which light is gathered by the sensor rather than by fixing the time and reading the absolute exposure after that fixed time.  The response curve could be dynamically determined during the exposure while avoiding either overexposed highlights or underexposed shadows, as long as the exposure was long enough to gather light for the shadows.  With this, you wouldn't set exposure on the camera, only aperture.

Of course, we could take this one step further.  At each pixel, we could record the entire light gathering curve over time during the exposure and post process this into the image.  Perhaps this is what cameras will do 10 years from now...  You could think of this as watching a photo print in the developer in the darkroom emerge from blank paper and controlling during when to stop the developer by painting stop on parts of the print when you were satisfied with the luminance.

Hmmm... I wonder if I should patent this idea ... :-)[/font]
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Ray
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« Reply #7 on: May 31, 2004, 10:44:46 PM »
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[font color=\'#000000\']Actually the challenge of increasing dynamic range by measuring the relative times it takes for a large number of megapixels to fill up would require a time measuring device far greater than a billionth of a second. Each extra stop of exposure is going to blow an increasing percentage of the photosites. If you want a hand-held shot with a telephoto, even with IS, you probably need 1/250. If a certain number of photodetectors are going to 'fill up' within say half the exposure time, ie 1/500th, and you can time those events, then you gain 1 stop in dynamic range. If a smaller quantity fills up whithin 1/1000th sec, you gain another stop, and if a yet smaller quantity fills up in 1/2000th sec, you gain 3 extra stops of DR, and so on.

For such a system to be worthwhile, you might need to time the relative fill-up rate of, say 3 megapixels within 1/4000th of a second, not to mention the time it takes to apply an algorithm to the different rates.

It might be possible  Cheesy .[/font]
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audibeara6
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« Reply #8 on: May 22, 2004, 10:08:58 AM »
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[font color=\'#000000\']I was looking at getting the 10D but now am considering the 1D Mark II. Are there any disadvantages to the Mark II over the 1Ds? I know that you can't go above a f/5.6 on the 10D, how about the Mark II? Also any thing that should make me want to stick with the 10D over the Mark II? Except for the price [/font]
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Paul Sumi
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« Reply #9 on: May 22, 2004, 12:02:24 PM »
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[font color=\'#000000\']
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I know that you can't go above a f/5.6 on the 10D, how about the Mark II?
Are you referring to aperture for auto-focus?  I don't know what the AF minimum is for the 1DII.[/font]
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Bobtrips
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« Reply #10 on: May 22, 2004, 01:30:29 PM »
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[font color=\'#000000\']"greater dynamic range"

How does one know?  Seems like there should be some easy way to measure dynamic range.  (Maybe there is and I'm not aware.)

When I look at a 'test strip' on my CRT vs. LCD monitor I see more 'steps' on the CRT - the LCD doesn't have the range to let me discriminate between the steps at the ends.  Can't something such as this be used with digitals?[/font]
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didger
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« Reply #11 on: May 22, 2004, 04:12:31 PM »
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[font color=\'#000000\']
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"greater dynamic range"
From the great amount of reading I've done about this, the bottom line is that all these sensors (with maybe Fuji FinePix excluded) have the same dynamic range.  It's locked into the basic technology.  If your camera can shoot and save raw, then with proper conversion and processing you'll have the maximum dynamic range possible for digital camera sensors (better than slide film; not as good as negative film).
As for 1ds vs whatever.  For today's ultimate DSLR quality no one contests that 1ds has no rivals and the advantages have already been mentioned.  I could mention another consideration, however.  There's places I simply would not take such an expensive camera, like for example traveling extensively in third world countries using public transportation and staying in cheap hotels.  I could recover from having a $2000 outfit stolen, but $6000 for a camera body alone would be a big hit.  In a place like India $6000 represents several years of income for many people, and therefore a huge temptation.[/font]
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didger
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« Reply #12 on: May 22, 2004, 10:57:32 PM »
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[font color=\'#000000\']Well, I've been going to India very regularly since 1972 and for some time I've been spending 6 months out of the year in Bombay.  I love the culture and basic human and family values and the people of India more deeply than I can say and the incredible experiences of generosity, hospitality and honesty and simple unassuming affection have been far more impressive than any experiences of scams and deception.  Home is where the heart is and my heart is in India no less than here.  However, with so many people and so many extremely poor people, even a very small minority of dishonest people still means a lot of dishonest people.  Reading an Indian newspaper is as appalling and depressing as any US newspaper.  I wouldn't leave something valuable exposed at the Delhi main railway station for a second and I sleep on top of any valuables on a second class train.  Thieves may not know specific models of cameras, but they'd be able to see that something like an eos 1ds is not a point and shoot.  I've witnessed flat out jewelry grabbing theft on trains and I know people that have been ripped off in various ways in India. In some third world countries I'd have some concern for my personal safety if I were carrying anything obviously valuable.

You only need to lose a $6000+ camera once to ruin your whole day.  If I get into serious photography in India (so far my long stays have been all business or visiting a spiritual retreat) I'll take my brother's eos 10d and Sigma 24-70, not my own 1ds and a bunch of expensive lenses.

In case you want to read something totally off topic, you can check out the India page on my website, about my experiences with my Indian business partner and our employees.  Nothing but positive, beautiful, incredible experiences and impressions.
http://www.didgeridoings.com/India/India.html[/font]
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Lin Evans
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« Reply #13 on: May 24, 2004, 04:01:15 PM »
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[font color=\'#000000\']
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From the great amount of reading I've done about this, the bottom line is that all these sensors (with maybe Fuji FinePix excluded) have the same dynamic range. It's locked into the basic technology

This is only true of consumer fixed lens sensors. The sensors used in pro level equipment vary from a bit over 8 stops to 12 stops. Canon's Director of Technical Services - Camera Division, U.S.A., Chuck Westfall says that Canon has measured the 1DS at greater than 8 and less than 9 stops of dynamic range. The 1D Mark II was measured at > 9 stops. Digital scanning backs such as BetterLight, etc., have up to 12 stops per manufacturers.

Now - the issue is measurement and how it's done and whether one uses the capacty of the sensor or the capacity of the sensor with a single exposure (not the same thing) in measurement. Who knows.....[/font]
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Lin
Lin Evans
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« Reply #14 on: May 25, 2004, 02:05:34 PM »
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[font color=\'#000000\']Hi Gary,

Yes, it's difficult to know exactly how the measurements were made and even more difficult to set a standard for these things which in some way equates to a film base which some have a better feel for.

One thing is certain, sensors have the ability to hold more dynamic range than can be captured with a single exposure aperture. With my Kodak DCS-760 and using Kodak software, it's very easy to go two stops beyond the apparent DR in the capture. Even more important is the fact that one may expose for highlights, shoot, expose for shadows and shoot an identical frame, then combine the two frames in software producing a result which has a couple stops more than can be obtained by a single RAW exposure and combining two conversions using the extremes of exposure compensation.

This means that at least in theory a manufacturer could design a lens with a variable aperture which could shift during the exposure and tap the "potential" for much greater dynamic range latent in the sensor.

Best regards,[/font]
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Lin
Lin Evans
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« Reply #15 on: May 25, 2004, 06:18:07 PM »
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[font color=\'#000000\']Hi Ray,

Two separate exposures later combined or two frames as a "double" exposure without dumping the first before the second occurs with the "combine" operation occuring in firmware would essentially be the same. Actually, it's already been done by Fuji (allowing double exposure) except it requires two presses of the shutter. What I'm theorizing is that it would be possible to combine electronically the the steps of exposure capture, different exposure capture with a single press of the shutter, especially since the majority of digital instruments with the exception of CMOS sensors have an electronic shutter anyway. Even the Canon EOS-1D only uses the mechanical shutter essentially to protect the sensor and gets its 1/500th flash sync and 1/16,000th shutter speed via the electronic shutter.

As it is presently, it takes two exposures to really take advantage of the entire dynamic range potential of the sensor. The down side is that we must combine the two in software selecting the appropriate portions of each for the final extended dynamic range composite. By combining the steps in an electronic sensor it "seems" that it would be fairly easy to accomplish much the same thing thing with a single press of the shutter and let the electronic switching and firmware take care of the remainder.

Hewlett-Packard already has a firmware feature on their consumer digicam which essentially duplicates the PhotoShop CS "shadow/highlight" function, and this approach could be used with the double exposure feature such as Fuji offers in some models to render a greatly enhanced dynamic range photo. Just meter on the highs, meter on the lows (sort of like the 1D Mark II offers) and press the shutter once rendering a double exposure processed entirely within firmware.

I don't know enough about the internals of present sensor technology to be certain this is possible, but it certainly seems logical to me that it could be done.

Best regards,

Lin[/font]
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Lin
Lin Evans
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« Reply #16 on: May 25, 2004, 07:45:10 PM »
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[font color=\'#000000\']Hi Ray,

I'm not certain of exactly how the process works. For example, it "could" be that the processor is dumped between exposures to a buffer then later combined but I'm suspicious that it may be done differently.

Let's take an example. The image below is from one of my Fuji digicams (S7000Z) which has the "multiple exposure" feature. You shoot, then you use the toggle switch to make a decision about saving the image to the card or continuing. You press the right arrow on the toggle, expose and shoot a second time or third or Fuji says "no limit" then when you are finished with exposures you press the center "O.K." portion of the multi-switch and only then is the file written to the card.

I'm assuming that if it were being written to a buffer there would be a very small number of exposures possible before filling - especially at the 12 megapixel interpolated file size on the S7000Z. But I've made dozens of exposures just for the sake of experimentation and there seems to be no limit. I just shot three quick exposures each at a different focal length for the image below. It would seem that this type technology combined with what HP does with "shadow/light" could possibly be used to greatly expand dynamic range to the limits of the sensor's ability to hold detail at the tails of the curve???

Lin

[/font]
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didger
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« Reply #17 on: May 25, 2004, 10:01:53 PM »
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[font color=\'#000000\']I don't care what amazing reports of vast latitude there are for any sort of digital sensor.  I share the skepticism about these claims and how they were arrived at.  I figure to always go out with a tripod and to do bracketed shots if I have the slightest doubt.  Blending in Photoshop is quick and easy and bomb-proof with the $20 Miranda plug.  Compact flash at $200 for 4 gb means you can "waste" lots and lots and lots of shots in the field, even if you only save raw and you don't bother to delete anything until you download.  

Better way too many pictures than any great shot that doesn't have all the latitude you thought it ought to have had.  Canon nerds won't sponsor your next trip to re-shoot!![/font]
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Lin Evans
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« Reply #18 on: May 26, 2004, 12:42:54 AM »
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[font color=\'#000000\']It's a natural progression from questions asked about advantages of the 1D Mark II over the 1DS. One of the advantages is increased dynamic range and questions about that have lead in a circuitous route here.[/font]
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Lin
Ray
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« Reply #19 on: May 26, 2004, 08:46:00 AM »
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[font color=\'#000000\']As for a previous comment that this automatic in camera double exposure and blending being potentially superior to bracketing and saving both raw images for later blending; NO WAY! Even without the obvious problem that this procedure would have to take some time, and thus be even more sensitive to camera motion, there's also the problem that you have no good visual feedback to see if it really worked right; just a littly tiny LCD camera display. Blending two images in Photoshop gives you lots of options for exactly how to do the blend and thus getting the best possible blend and you can see exactly what you have for each trial.[/font]
[font color=\'#000000\']You might have noticed, Didger, I also wrote that such blending software in-camera would have to be very good. Everything takes time, but as processor speeds increase and buffer sizes increase, saving two RAW images and/or shunting them off to a separate buffer for blending should eventually be possible in the blink of an eye.

You don't need visual feedback if the software or firmware is working properly, considering the exceptionally high dynamic range of the combined images, and I see no reason why the camera should be more sensitive to motion. The concept is that it should be less sensitive to motion because the time interval between exposures is reduced. Such a system should allow hand-held dual shots more often. The problem with my D60 is that autobracketing takes over a full second. I don't think the 1Ds is much faster. Fortunately the two shots that are the most useful (the underexposed and the overexposed) are consecutive, so the total exposure time from the beginning of one shot to the end of the next is probably often less than a second, but not by much. Even with a tripod, that's not ideal. A lot of movement can take place within a second  Smiley .[/font]
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