Cedric, it's very hard to communicate how sharp a print is (or should be) in writing or verbally. If this helps any, consider that your enlargement ratio (linear) is about 4X; this is roughly equivalent to a 4" x 6" print from a 35mm neg. So, do your 16x20s seem to have roughly the same sharpness as that, or are they much worse?
Far be it for me to correct our host, but a 16x20 print from 4x5 is a 16X enlargement, not 4X. (It's 4X north-south and 4X east-west, thus yielding 16X.)
Sorry Chad but you are wrong, magnification is viewed as surface area, so 8x10=80 square inches, 16x20=320 square inches, divide 320/80 and you get 4, thus a 4x magnification.
I'm Sorry to comment like this but i'm following this post closely (similar experience), isn't the medium 4x5 trans. not 8x10.
Thanks Ck
ah, yes.....sorry..I was thinking of 8x10, my apologies to Chad he then is correct 4x5 to 16x20 is a 16x enlargement...
When enlarger lens manufacturers publish "useable" and "optimal" magnification ranges, they would consider a 4x5 enlarged to 16x20 to be a 4x magnification.
For example look at the Rodenstock web page below: http://www.rodenstockoptics.de/pg3.html (Remove any spaces in the web address added by the response software).
Notice that the 50mm Rodagon has a usable magnification range (what Rodenstock calls "scale") of 2x - 15x and the optimum is 10x. El- Nikkor specifically uses the term "magnification range" in their English language specifications (not available on web).
If magnification range was measured based on area, then an 8x10 inch print from a 35mm negative would be a about a 60X enlargement. (8*10)/ (24*36/645.16). There are 645.16 square millimeters in a square inch. Measured by the increase in the longest dimension, an 8x10 enlargement would be about a 7X enlargement. Obviously when Rodenstock (and other enlarger lens manufacturers) use the term magnification range (or scale) they are using the later definition (increase in longest dimension), and not based on total area.
I am not sure if there is difference between the meaning of "magnification range (scale)" and "enlargement factor." But these terms can be confusing depending on their intended use.
Michael, there is a difference between magnification and enlargement. For example for a 35 mm neg (to take your example) if we MAGNIFY the longest part to and 8x10 print then you are correct, 25.4/3.6=7.05, BUT when you are talking about enlargement you are actually magnifying an AREA not a line, which means that a grain of silver halide will look 70 times bigger in an 8x10 print than in a 35 mm print because you have enlarged it's AREA 70 times. If we look at magnification scales then an 8x10 print from a 35 mm 100 ASA would be grainless at 7x since we are talking about micron size grain, thus if you go from 2 microns to 14 microns the difference is not noticeable, but going from 2 microns to 140 microns then you can beguin to see the grain. (BTW I used imaginary numbers for size, I don't know the size of a grain of silver halide..:-0).
Scale in Rodenstock literature is lineal magnification.
4X on 4x5 lens means a 16 x20" print.
jorge,
could you explain in more detail your distinction between magnification and enlargement? just the first sentence or two of your last post as i'm having trouble understanding. if i switch the terms the sentence still makes sense to me so i don't think i understand.
"Scale in Rodenstock literature is lineal magnification."
isn't this because enlargement is commonly the same (or close to the same) in both dimensions? it is unusual to enlarge only one dimension of a piece of film, except of course cropped panoramics. as a 16x enlargement could be 16x only one way, 4x both ways, 8x one way 2x the other, etc., it seems easier to think of it in terms of line and not area. at least the manufacturers can agree on terms.
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