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Author Topic: thom hogan FX vs DX  (Read 16765 times)

Ray

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Re: suddenly, a tiny VF image of the subject is unimportant?!
« Reply #20 on: May 08, 2013, 05:21:56 am »

However, surely different photographers will put different relative weights on the image size disadvantage vs the "peripheral vision" advantage, so I do not see how you can categorically declare that one "offsets" the other as if the VF image size deficit is rendered irrelevant.

Of course, BJL. We're not talking about objective, non-subjective facts here, such as the resolution of a lens in terms of line pairs per mm at a particular MTF. All models and all formats of cameras have numerous advantages and disadvantages when compared with each other, and such advantages and disadvantages will tend to have a strong subjective element which is affected in general by the circumstances, experience, desires, goals and shooting style of the photographer, and in particular by the requirements for a particular shot at a particular moment of time.

We both agree that the smaller size of the view of the intended composition, as seen through a 135-format viewfinder in DX mode, is a disadvantage. And we both agree that the consequent effects of being able to see in that viewfinder parts of the scene surrounding the intended composition, is an advantage.

Unfortunately, there are no objective units of measurement which allow us to quantify such advantages and disadvantages and put them on a scale to see which is more significant.

Regarding the D800E, the main advantage of DX mode, in my subjective opinion, is when using a DX lens. The black-lined, DX-size frame in the viewfinder should be a useful guide to indicate that image quality outside the frame will likely be very poor.

Since I don't own any Nikkor DX lenses, I've never used my D800E in DX mode. I prefer to crop to taste in post processing. For me, the main advantage of using a D7000, for example, in addition to a D800E, would not be because of the enlarged image seen in the D7000 viewfinder, with a give focal length of lens, but because carrying two such cameras, with zoom lenses attached, can save time and hassle in changing lenses.

However, neither of these two advantages, the greater magnification and the avoidance of changing lenses, is sufficient reason for me to carry my D7000 as well as my D800E when I go out shooting. I need a greater incentive, and I'll have it with the D7100 which provides a 50% increase in pixel count compared with the D7000 or the D800 in DX mode.

Now, it's understood that a 50% increase in pixel count is not a 50% increase in resolution. It's only a 22% increase in resolution, but a 22% increase in sensor resolution is probably, on average, about equal to the increased resolution that a good prime lens has compared with a moderate quality zoom.
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BJL

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Actually, I am glad for new less dogmatic thinking about VF image size
« Reply #21 on: May 08, 2013, 10:35:03 am »

... We both agree that the smaller size of the view of the intended composition, as seen through a 135-format viewfinder in DX mode, is a disadvantage ...
Strange then that my briefly noting that fact about VF image size has produced hundreds of words of "yes, but ..." variety, when all the hundreds of previous criticisms of smaller VF images inspired nothing but beard-stroking statements of agreement. To be clear, I agree rather more with the new arguments in defense of smaller VF images than the previous vigorous disparagement of any VF image smaller than what the writer was most familiar with. My amusement is at what the change reveals about the previous consensus that a smaller VF image was always a significant, even "deal breaking" disadvantage.

I instead long ago found that the magnification of "0.7x at normal field of view" (to put it in format neutral terms) as seen in most AF 35mm format SLRs is a bit too large for convenient composition, due to the excessive eye-ball movements needed to check all the edges and corners of the composition, and instead around 0.6x is my ideal. Once upon a time, manual focusing benefitted from a larger image even up to 0.8x or more, and to the extent that some people still sometimes have to manual focus through the optical VF of a DSLR which lacks the focusing aids of older manual-focus-only SLRs, maybe even 0.7x is too little, but that is no longer my problem.

I suspect that what is really happening is this: many people, like me, find that with the new technologies of AF and enlargement for manual focusing in live view mode, a somewhat smaller VF image is far less of a disadvantage than it used to be, and may even be an advantage if the downsizing is not taken too far. (One hint is that EVF image sizes, which could be almost any size by choice of panel size and brightness, are in the range 0.6x-0.7x at normal FOV.) But the shift to smaller VF image sizes has been criticized for a variety of reasons, ranging from a legitimate need of those who often focus their SLRs manually through the OVF, to the familiarity-driven preference of many older more experienced photographers who are uncomfortable with the new smaller VF image sizes, and get a sense of "tunnel vision" from them. (Maybe just having additional, if somewhat irrelevant, imagery around the actual crop framing removes the discomfort of that tunnel vision?)

So if the "digital tele-convertor" 1.5x crop most is used almost exclusively with auto focus, it might not matter so much that the image of the scene actually being photographed is about as small as the smallest Four Thirds DSLR VF images, which were so widely and vigorously disparaged at sites like this one. Times change; people too, but more slowly.

« Last Edit: May 08, 2013, 10:52:31 am by BJL »
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Ray

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Strange then that my briefly noting that fact about VF image size has produced hundreds of words of "yes, but ..." variety, when all the hundreds of previous criticisms of smaller VF images inspired nothing but beard-stroking statements of agreement. To be clear, I agree rather more with the new arguments in defense of smaller VF images than the previous vigorous disparagement of any VF image smaller than what the writer was most familiar with. My amusement is at what the change reveals about the previous consensus that a smaller VF image was always a significant, even "deal breaking" disadvantage.

Not strange at all, BJL.  The D800 was the first full-frame 135 DSLR to have the pixel density of the manufacturer's most recent, prosumer cropped-format DSLR, at the time it was released. The advantages of that equal pixel density of the larger format far outweighs the disadvantages of the smaller viewfinder image in DX mode, especially when that disadvantage is at least partially offset by the peripheral vision surrounding the DX frame within the larger format.

I think you're making a mountain out of a molehill, BJL. I can't remember ever commenting before on the inadequacy of viewfinder size. For me there have been far more serious camera inadequacies that have caught my attention, such as noisy shadows, poor DR and SNR, low resolution, inaccurate autofocussing, slow frame rate, and so on.
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