28 July 2013

testing 1,2,3 zooms to 200mm

I stood on my porch with my K-01 and tested three xx-200mm zooms at 135mm, 200mm and for close focusing.  They each did the job pretty well, which is no surprise nowadays.

I locked aperture and ISO but the left one does not show the 0.7EV exposure boost that I thought they all had - and no stopping the clouds in any case!  Anyway, the 18-200 Sigma looked best for colors, the Promaster 28-200 perhaps a touch sharper, and the DA50-200WR the least color-fringed.  No surprise since it's the zoom with the least range to compensate for, and a later test looked sharper than the first go.  The 28-200 is an older copy of this oft-remade Tamron lens, and color fringing has been its weak point for quite a while in my experience, which goes back to my Alpha days in 2008.  This version has 72mm filter threads and is about 100 grams bulkier than the more recent models.

One thing is clear in close-focus: the longer the zoom's range the closer you can get, but the least like 200mm the scale becomes.  Long-reach zooms must be made this way to do what they do, and it's very clear when popping off the 18-200mm and sticking on the DA 50-200WR; I had to step quite a way further back to reach focus, but the resulting image scale is actually larger!

No major surprises revealed, but good to know.