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A question of judgement

Discussion in 'General Equipment Chat & Advice' started by Brian, Aug 22, 2001.

  1. Reading

    Reading Well-Known Member

    Yes, it is cloud cuckoo to most of us, but so is £7000!!!

    He is actually in a rather difficult situation of reviewing a camera aimed at professionals in a magazine supposedly aimed at amateurs.

    He seems to have geared his review to the camera rather than the magazine. Right or Wrong, I dont know. Would be nice if he stated this as the case though.
     
  2. phil

    phil Well-Known Member

    It it to your original question to which my answers have been addressed. Let me clarify things if I can:

    The pixels in a camera capture an image at a set resolution and pixel size which both equate to the halide grains in an emulsion - OK to get full resolution at the smallest pixel size you image would be the size of the sensor - equates to a contact print. However, as soon as the image is enlarged onto what ever format - screen or paper- no more resolution is gained only the size of the pixel (PICTURE ELEMENT) increases. So on a screen with a comparable resolution to the original sensor if the image size is doubled the original pixel now becomes an array of four pixels all of the same colour. increase again and it becomes 16 pixels all of the same colour then its 64 etc etc (called the quad tree effect which also affects memory storage). Although printers and screens may have a higher resolution this does not in any way affect the image quality, generally on a screen a small image is sub sampled and so most of the pixels are not displayed however on enlargment the pixel resolution is quickly exceeded and so the elements increase in size. And it is this limit to which Damien refers to in his limit of a 5x3 print. Beyond that limit the grain becomes noticable. As we all know halide film is more than capable of exceeding a 5x3 print due to the original resolution in the halide grain arrangement. And so until the sensors have a greater resolution or algorythms exist to perform subpixel interpolation the resolution of a digital camera picture will remain inferior (soory you digital boys but its true). Useable, flexible and convienient but inferior. Try it for your self put an image into paintshop pro or the like and keep enlarging. It doesn't take long befoe the original pixels (from the image) become blocks of monotone or should that be monochrome. and so the capability of the camera's resolution to the human eye is reached and then work out the linear dimensions of the image it won't be that big. Some printers and software will perform an interpolaition upon images to remove the enlargment pixilation ( I had a picture published on the front cover of a journal and was amazed) but this increase in resolution is artifactual and is done (I think) by resampling the original picture at a higher screen resolution and the applying a smoothing filter (a many pixel moving median filter is probably the one that is used) to decrease the pixilation alos a dye sub printer does wonders.

    OK, so sayeth Me _

    and Brian I think I'll go for CuSo4 and not NaCl it shpould make you fizz more!!!

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  3. Reading

    Reading Well-Known Member

    Finally, I agree with you here.

    Well put, actually.
     
  4. phil

    phil Well-Known Member

    My feelings on this thread are made very clear below but lets extend the issue shall we. How do your D30 images look when they are projected? because to be quite honest a 10x8 print is small potatos to a projection screen!!! As I have said below everything rests with the sensor resolution cos its all down to a very old adage in image anlysis circle - Crap image in; Crap image out! Don't get me wrong I'm not knocking your D30 I'd love one but in the practicalities of image resolution it ain't there yet!!! But I do take the point that generally you can tell but try to explain that to someone who uses iso 25 film in their camera and suggest they move up to 1600 and say that it won't make much difference!!!!!!!!!!!! Its all the same........



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  5. Reading

    Reading Well-Known Member

    My word, I am agreeing again - almost!

    Sensor is not EVERYTHING - lens resolution comes first, but on the proviso that good lenses are used, sensor resolution is way behind.

    Love the analogy about 1600ISO film, by the way. Although digi buffs will say that 1600 film looks more grainy due to the space between the grains. If the grains were expanded to fill the available space (as in digicams), then the ISO 1600 film would 'appear' better that it actually is, and the difference would be less noticable. Still give us Velvia or Kadachrome any day, eh?
     
  6. Brian

    Brian Venerable Elder

    No, No Phil not the CuSo4, No, anything but that.

    A Very Upset Snail&lt;img src="/img/wwwthreads/frown.gif"&gt;

    P.S. So as not to deviate. For anyone reading this article with a view to taking up digital photography, I would have thought, off putting would spring to mind. Here we have the camera with specifications that was talked about in these very threads only months ago. But the professional reviewer has in fact said that for anything over 5"x3" 35mm film is better, he now wants 12 million pixels.

    Hardly encouraging for the poor guy thinking about laying out £6/700 for his first foray into the digital world.

    Please don't Phil, I promise to be a good Snail. I'll only go after nasty Steves garden, or his son's.
     
  7. David Stout

    David Stout Well-Known Member

    Projection is new territory for my digital camera images but I am about to find out shortly as I will have access to a high quality data projector.

    I don't see any point in transferring a digital image to slide because this introduces another step that could lead to image degradation. If I wanted slides, I would have shot on 35mm in the first place. Horses for courses as I keep saying.

    David

    I prefer a sharp ISO 1600 image to an unsharp ISO 25 one. (This is a standalone statement as I'm not sure where it fits into this debate!) :)
     
  8. Benchista

    Benchista Which Tyler

    Well, my contribution, for what it's worth.
    With my equipment I can produce A4 prints of perfectly acceptable quality from digital or film. I have a 3 megapixel digital camera, a 3 colour plus black printer and a 1950 DPI film scanner, none of which is exactly state of the art. Prints from the digicam of images teken in TIFF mode are slightly better than my 35mm scans, but if I hang a print on the wall I can't tell the difference between any of them at a normal viewing distance.
    Now, if I had a better quality printer and a 4000 dpi scanner, perhaps the inherent quality advantage that film has might be apparant. But I haven't, and I'm actually quite happy with my results - for now. Once more it comes down to what your expectations of "acceptable quality"really are. The theory doesn't matter, all that actually counts is the results.

    Nick CRIPN
     
  9. phil

    phil Well-Known Member

    I beg to differ - I see it as a perfect analogy to ccd sensor resolution and the points I have made in the thread! iso 25 would equate to a high density small pixels sensor with its benfits of resolution but poorer light gathering capability, whereas iso1600 is a larger pixeled lower density sensor with reduced resolution but higher sensitivity. I'm not having a go at digital per se but the limitations upon enlargemt exist and must be considered in the context of resolution and empty magnification (i.e. once the resolution has been exceeded then anly further increase only compounds the problem) But once again the fundamental resolution of the camera will affect everything. You may have access to a high resolution projector but unless you picture orignial has suffiecent resolution then there is little point! As you have said before this may be a academic question in terms of picture reproduction but hey I am an academic and the effects are real and must be considered if not why bother trying to increase sensor pixel density in the first place lets all go back to single megapixel analogue cameras and have done with it!!!

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  10. phil

    phil Well-Known Member

    Well said and at the end of the day thats what counts but if people get hung up on pixel counting ( always remember to divide the number by three cos of the separate rgb sensors) they should be aware of the limitations and perform a cost benefit analysis i.e. will paying £7000 give me anything more!! The main point from the all of my ramblings to this thread is that quality coems from pixel density and not absolute number!!!

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  11. David Stout

    David Stout Well-Known Member

    Further inconsistency

    Quite by accident last night I picked up the 21st July issue of AP where Damien Demolder tested the Nikon Coolpix 995.

    Let me quote from his summary:

    "This is an outstanding digital camera" (remember it's only 3.3 Mp)

    "In terms of specification there is little missing beyond a six million pixel chip" (Now he's got a camera with 6 Mp in August he wants 12 Mp! Can't he make his mind up?)

    "Picture quality is excellent for those wanting to output prints of up to 5x7in on a good printer"

    The last point is really interesting - "picture quality is excellent". Yet, a month later he is claims that unless you use a camera with twice the number of pixels and print at less than half that size (5x3in) you won't get film quality.

    Damien's standards are as changeable as the weather it seems. Either that or he has shares in the 35mm film industry.

    I come back to my original point - forget the hypothetical comparisons between digital and 35mm. This is for the pub over a pint. Instead, come down to earth and assess the final printed image.

    David
     
  12. phil

    phil Well-Known Member

    Re: Further inconsistency

    Sorry to harp on but!!!!!

    If I bought a camera that only gave pictures up to 5x7 I'd sell it!!!

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  13. SCT

    SCT Well-Known Member

    Re: Further inconsistency

    Interesting. Perhaps Damien should research previous reports before commiting pen to paper.

    But more worrying. Did he test the product(s) before he drafted his report.

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  14. David Stout

    David Stout Well-Known Member

    Re: Further inconsistency

    I quite agree. If it takes a 6 Mp camera to produce a decent 5x3in print then my D30 (3.1 Mp) should be capable of producing nice 2.5x3in prints.

    Anybody want to buy my D30 - decent prints though postage stamp size!

    David
     
  15. Glenn Harper

    Glenn Harper Well-Known Member

    Re: Further inconsistency

    Only I'm allowed to harp on !

    Here's a current quote from one of AP's 'rival' mags:

    "The latest 3 megapixel cameras will deliver fine quality 10 x 8in prints and we've seen quality 30 x 20in prints from the Nikon D1x ...."

    and later....

    " That said, the potential image quality of a medium speed, fine grain 35mm emulsion is far better than anything offered by even a 5 megapixel camera"

    It goes on to say though that if you only want to make prints to 10 x 8in, then digital is a good choice. Other advantages of digital are also discussed.

    Glenn 'harp on' Harper
     
  16. phil

    phil Well-Known Member

    Re: Further inconsistency

    I'll give you a tenner for it!!!! As a last comment and I do mean last; to see a decernable increase in image quality required one of two things either smaller higer density pixels (if the sensor size is to stay the same) or 4 times the number of pixels in a larger sensor which would result in a 2 times increase in the sensors linear dimentions ie. change from 35mm to close to a medium format and so require less enlargement overall. Both have pros and cons of cost, flexibility etc etc. I prefer 35mm emulsion purely because all of the work (in an employment sense) I did and still on occasion do with digital cameras - hell I even tried to get quotes for a Nikon F5 with a kodak digital back not so long ago (by the way Nikon where's my blinkin' quote!!) Its horses for courses and my course is a halide one and to be quite honest my photogrphy is so deficient is so many ways (particularly time!) absolute resolution doesn't come into it. The message I am really trying to put over is that people should not just count pixels when considering cameras but the effect that pixel size will have on their final image. If your happy with you camera you one step a head of many people, and who wouldn't be happy with a D30 as it is at last a good sensor on the back of a good camera - as a complete package (at what I consider a good price as well -wish I had the readies). As such the sensor is purely and simply a film replacement and therefore should come under scrutiny as such as it just has. Perhaps we'll see the next generation of digital cameras turning their backs on the familiar 35 mm format and looking more like a Hasselblad -with good lenses and much bigger sensors!!!

    Who cares my last camera cost less than £50 and is so old in design terms I have to assure people its only 6 months old and not 60 years!!!

    P.S. I have asked this question before but got no answer - do you digital users see pixel blooming with bright light sources?

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  17. David Stout

    David Stout Well-Known Member

    Re: Further inconsistency

    On the one hand they admit that digital is good and can produce quality large prints (I know because I do it all the time) but on the other they say that 35mm is far superior. They can't have it both ways!

    Again, it is a matter of opinion based on hypothetical nonsense. The only way to really make a valid comparison is a side-by-side test of say, a D30 vs an EOS 3 with Provia, under identical conditions and with identical lenses.

    In fact, this has already been done by a professional photographer, Michael Reichmann, who concludes that a D30 digital image is better than a good ISO 100 slide film. See http://www.luminous-landscape.com/d30_vs_film.htm and read it for yourself.

    Michael's conclusion is based on fact backed up by hard evidence. I just wish camera mag reviewers would deal more with facts than personal opinions based on ill-thought out theory. They are becoming like newspaper journalists where you start to wonder what you should believe. It doesn't do them or the photo industry any good.

    David
     
  18. David Stout

    David Stout Well-Known Member

    Re: Further inconsistency

    &gt;Do you digital users see pixel blooming with bright light sources?

    Not on the D30 but I have seen it on Minolta, Epson and Canon compact digital cameras. Not sure whether the CMOS sensor influences this or the image acquisition and processing algorithms in the camera, or both.

    David
     
  19. phil

    phil Well-Known Member

    Re: Further inconsistency

    Is you d30 a cmos chip? thought the resolution on cmos's was still too low to be used on anything other that autofocus sensors - If it then wow! cos Cmos is so robust to sharp changes in contrast and very resilent to light flooding!!!

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  20. David Stout

    David Stout Well-Known Member

    Re: Further inconsistency

    This was one of the most remarkable things about the D30 when it was launched. The industry said that CMOS wasn't usable yet and Canon proved them wrong - it is a fantastic chip.

    David
     

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