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15th April 2008, 03:19 PM
Thoughts on new cameras - smaller versus larger pixels
I work mostly in black and white, and have recently been experiencing a makeover from darkroom to digital, and am making progress after holding out for quite a while.
I was making black and white print portfolios two years ago for classes pursuant to a masters on photography and bought a digital camera for the purpose of photographing my silver prints . It became very evident after a while that I was the only person in the program using film at all so I decided I had better get up to speed. I have an Epson 2400 printer which does do excellent black and white prints so now I feel that the output side is getting up to my standards of quality.
The camera I bought then and still have is a Canon Rebel, the original, and I own a 55 compact macro and a 24-70 f2.8 EF L series zoom, which is excellent. I used to use all Nikon equipment (all manual), plus I have an enormous Mamiya RB67. I have kind of skipped a digital generation (Canon 20 D, Nikon D70) and am about to get a new camera. I have been thinking about the 5D, as several people I know use the full frame 16mp Canon and swear by it. I also know plenty of artists who like the detail they get from the D2x. My opinion is that with quality lenses its probably not an image quality issue except in some circumstances. I have read articles that claim that smaller pixels have greater resolving power ( see here - http://www.lonestardigital.com/D2X.htm) , but am convinced that larger pixels are more efficient light gatherers and have less noise, and I also like the Airy Disk reasoning that you wrote about so clearly.
I tend to like extreme depth of field and tend to use small apertures to get it. I do small still lifes, and some intimate landscape and architectural work. I often find myself in low light situations as well. I still like to make "straight" photographic images, f64 school-wise, although digital makes me explore new things as well. The new vibration reduction lenses are an attractive option for using a relatively slow shutter speed to keep the aperture smaller without resorting to a high ISO. I understand that if one uses a tripod then this feature must be deactivated as it actually causes blur. I would say that I am still working developing a personal style and on technique to get the most out of digital files.
It is somewhat annoying that there seems to be a sort of technical bifurcation, reminds me of PCs and Apples, or maybe Episcopals and Presbyterians, between the sensor sizes prevalent in the higher end SLRs and most of us consumers and semi-pros just have to make a choice and get out the checkbook. I can either sell the Rebel and the 24-70 lens and get a new D200 from Nikon, which looks to be an excellent device, or keep the lens and get a Canon 5D. I have seen image comparisons in which either type prevailed, so I think that in my young artistic career (I am 60 now) it will make little difference when compared to the importance of making interesting and artistically valid images.
Some analyses tend to obscure the relevant issues but your site is one that has much useful food for thought and for that I thank you. I think that many comparisons while valid are as relevant to the artist as the old arguments about the number of angels that can dance on the head of a pin. So I must take the plunge and hope that I can swim at a decent pace in this technological stream.
15th April 2008, 03:25 PM
I followed the link you have provided, and wholeheartedly disagree. Total resolution is a function of BOTH lines per mm and sensor size--basically the total pixel count. This means that it is actually a disadvantage that the pixel density of the D2X approaches 90 lp/mm because as that article says, this is beyond what most lenses can resolve (when not stopped down and at the edges). In this case, using a 35mm lens on a camera with a larger sensor and the same number of pixels in total (therefore a lower pixel density) would actually provide more real-world resolution. The thing to keep in mind is that a larger sensor has to be enlarged less to produce a given print size-- therefore not necessarily providing any less detail even if the lines/mm resolving power is less at the sensor. The D2X is a great camera and there are many reasons to make this your option, but I just want to be clear that this is not one of those reasons
If you do telephoto work, sports of plenty of flash photography then I would probably choose the D2X over the 5D, otherwise the 5D is a better option in my mind. I feel I am being impartial in saying this, since I do concede that I have a 5D. It will produce much less noise (particularly at higher ISO speeds), in addition to letting you keep your current lenses and providing more dynamic range (in this case, significantly more). Further, it will allow you to fully utilize these lenses; the 24-70 us a great lens and in my mind is a much better focal range on a full frame camera (much wider angle view). This way you are not throwing away any of the light from the lens as you would with a cropped sensor.
As far as depth of field goes, generally a smaller sensor will provide more dof for a given aperture and focal length (assuming that you maintain the same perspective). On the other hand, the pixels on the 5D are much larger and so these will not be affected by diffraction until a much smaller aperture. Diffraction becomes an issue on the D2x past f/9, whereas on a 5D diffraction does not degrade the image until much past ~f/14. This will of course require longer exposure times, but if you are using a tripod this is rarely a problem. For portraits this shallower depth of field very welcome.
Please also see the article at http://www.cambridgeincolour.com/tut...ensor-size.htm, which gives a much more thorough discussion of this topic.
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