Tamron 70-300mm F/4-5.6 Di USD
Before viewing the crops please read: I used a slightly different
part of the stamp scene for each focal length to make it clear each focal length should stand on it's own, because
there was no attempt to capture the exact same coverage at different distances, so do not compare crops
across different focal lengths. The Tamron crops below are the same as I used in the review.
indoor, controlled environment was selected (along with the stamp subject) to avoid heat shimmer and
other image destroying conditions you typically get with telephoto lenses outside in the Summer, especially here in southern
Arizona. Shooting indoors eliminates those problems, but forces me to use shorter focusing distances.
Fortunately, the distances used (and listed below) are in the bird or small animal range, so it makes
the cropped images more useful as opposed to very close focus test chart type shots.
most side-by-side comparisons, like this one, I warn viewers of getting too picky about which lens is the sharpest etc.
The real world differences between each lens may not be very noticeable (if at all) unless displayed side-by-side as I've
The Sony A900 was used for this comparison, along with a tripod, remote shutter and manual
WB. Bracketed manual focusing was used, with the resulting absolute sharpest shot used as the base for the entire set,
at each length.
APS-C users: the full frame mid-section crops below were taken from the same position
as where the APS-C corners would be.
The Tamron is a tiny bit longer (things appear
closer) at all focal lengths as compared to the Sony, which means the Tamron has a very slight advantage in this test.
Guide for beginners.
In case you aren't all that familiar with the nuances of image quality, I've added some circles with
numbers to help point out areas that you'll want to take note of. This image was taken closer than the real crops below,
so I could enlarge it and put in the numbers for you to see.
1. Look at the very fine detail here,
or lack thereof between the crops.
2. This block of lines inside the circle is just 3mm across.
Look along the white border on the stamp, with the less expensive lenses, it almost vanishes among the white from the cardboard
box background. A good lens will more clearly delineate the transition (acutance).
letters are all fuzzed up on the less expensive lenses, and clearly discernible with the good ones, even at wide open apertures,
it's the same issue as no. 3 above.