Equipment selection exercise.
'Butterfly Shoot'
Objective: to photograph butterflies of wing span say 30 to 70mm let us assume in each case an area of 30mm and 70mm side resp'
Chip sizes available
5D - 36 x 24mm 12.5Mpix (122pix/mm)
40D - 22 x 14mm 10Mpix (175pix/mm)
mag = image size / object size =
using 5D
24/70 = 0.343x
24/30 = 0.8xusing 40D
14/70 = 0.2x
14/30 = 0.467x
From above we need a range of: 0.343x - 0.8x or 0.2x - 0.467x
Which lens to use? or do I actually need to buy a 180mm Macro?
Assume using existing EF 70-200 ƒ2.8
Lens - Subject distance |
Magnification | |
Zoom @200mm | 1.4m |
0.17x |
Extenders | ||
1.4x |
1.4m |
0.24x max |
2x |
1.4m |
0.36x max |
Ext Tube | ||
12mm | ||
70mm |
555mm - 624mm |
0.22x - 0.17x |
200mm |
1110mm-3401mm |
0.24x - 0.06x |
24mm | ||
70mm |
402mm - 407mm |
0.41x - 0.38x |
200mm |
929mm - 1737mm |
0.32x - 0.14x |
500D Close up lens | ||
70mm |
500mm max |
0.21 - 0.14x |
200mm |
500mm max |
0.55 - 0.39x |
My choice is to use the EF70-200mm lens, 500D Close Up lens and take both backs
The only problem is where are the Butterflies? they are particularly rare this year (2008)
NB
1. The 180mm ƒ/3.5L Macro L-S distance 480mm at 1x
2. Despite 40D sensor being smaller it has a greater density 175px/mm as compared with the 5D's 122px/mm so at @100% pixel for pixel repro it is equivalent to a 19.6 x 30.8mm sensor at the 5D density