Just want to double check with you. Am I correct in assuming that we can always decrease the magnification by moving farther away... can we still focus?
Assuming we use the tele end: 300mm, the 250D would give a 1.2X magnification at a working distance of about 250mm (9.8 inches) and a 500D would give a 0.6X magnification at a working distance of about 500mm (19.6 inches). Now, while using 250D, we might be able to move away to increase the working distance and get a lower maginification which MIGHT be comparable to 500D? Ofcourse, what we need to compare is at what working distance while using the 250D we get the maximum magnification of 500D (0.6X)... is it 12 inches or say 17 inches (comparable to that of 500D). My guess would be somewhere in between... but it would be nice to have the number!
Just a thought since many consumer telezooms have 58mm filter size. This gives an additional option of using 250D as against just having the 500D available for the 70-200 f4s and f2.8s...Show more →
Someet ,your working distance will be constant, but if you are at 300 and need more in your pic just turn the zoom down with out having to move back , then refocus.
Tom Hicks wrote:
Someet ,your working distance will be constant, but if you are at 300 and need more in your pic just turn the zoom down with out having to move back , then refocus.
I'm just nitpicking here - but I find that with a cheaper zoom (like the 70-300 that I use) after zooming in or out you will have to refocus - because the process of zooming actually makes your lens shorter/longer so your distance to subject changes. You don't always have to move closer or further away but you do usually have to refocus.
Just a note about close-up lens selection...
Depending on your filter size, you might want to consider a Nikon 6T. It's a +3 diopter that can be had for about $50. I've got one in 62mm that would be fine on that 100-300 with a step down ring.
I like the results I get. My set up doesn't give me as much magnification because I've only got 125mm on the long end of my lens. http://www.pbase.com/dazedgonebye/image/40597709.jpg
smaniscalco wrote:
So, how are you mounting that diffuser?
It's funny - I was asking Tom Hicks the same question a month ago. Basically it is held on by putting it between the rings or between a ring and the barrel of the lens and screwing it on to hold it in place. Works pretty well.
I got an FD 50mm macro and glued the lever in back so I could set the aperture manually. Then I glued it to a 2" od aluminum pipe that I cut to about 1". Making an extention tube. And then I cut out a body cap and glued everything to that. I know have a very sharp 50mm that I set the aperture manually and take decent macros with. The only problem is the limited adjustability of focus.
