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Reviewed by
lapratho
, Expert
Price Paid
$79.00
at Cameta Camera, eBay
Photography Experience
21+ years
, Fine Art
Summary
I was skeptical, but for the price I figured I couldn't loose much on a reasonably fast zoom lens.
This is a first impression:
Right away:
This is NOT a soft lens, it is actually pretty sharp. I just played with this little marvel and made a few shots after taking it out of the box, and I think I know why people made the comments about this lens being soft.
Trust me, those soft shots are likely a victim of autofocus/bad-focus habits and not understanding depth of field.
At f2.8 ANY lens is liable to have a shallow depth of field. It is a most basic photographic concept, that the wider a lens is opened, the better it needs to be focused, and the shallower your DOF is, ie your model may end up with a sharp nose but mushy ears and hair that almost looks like it was shampooed, with nothing visible in a fuzzy mess all around ... well, come to think of it, that might be an award winning portrait ... never mind ...
Back to focus and sharpness:
The whole trick is this: focus! With modern SLRs this is a bit tricky - with the average tiny digital viewfinders one is more or less at the autofocus system's mercy with several models out there, and with the autofocus, less is more. Forget your 11 point overkill systems in 128 zones etc - just measure light on subject, hit AE lock to lock exposure, concentrate on pinning the subject center in spot focus mode, hold it, recompose, fire. Under 2 seconds and well worth it and beats fiddling with AF zone selections until the last snail has run over the finish line. Just stay in spot mode. Simple! That way you KNOW what you're focusing on and shooting, and results are almost guarranteed.
The technique is simple and can be much faster and more conveniently adjusted than fiddling with autofocus "intelligent" zones. Enough said.
Once I said no more film from here on - but then of course the full sized viewfinders of my old Ricoh gear will have me burn a roll now and then.
If you've never held an OLD Ricoh KR or Pentax metal body with their straight 1-1 views through a 55mm lens (keep both eyes open, and the viewfinder image is the same size as the naked eye's) you cannot appreciate this point.
Sooo ... this lens might also come in handy with my "vintage" manual focus KR-5 and KR-10 Super, if it werent for a fairly stiff focus action in manual, especially with the little snag I mention below, ie friction by the drive shaft on a strictly manual-focus body. Thathowever, is not a problem on an autofocus body!
So, if you're looking for a GREAT and fast lens for dim situations in those nightly showrooms and a range that makes it a near carry one for all occasions on an autofocus body on a budget, look no further, especially if you can snag this puppy at under $100 the way I did!
For a manual focus body, hand focusing could become a problem, but if you're handy like I, a little filing down of a critical spot on your camera mount will make the action a lot easier.
Considering the excellent optics with crisp and nicely conrollable definition good colors (more daytime shots are needed though for that to be 100% qualified, it's dark now and lamplight only), getting a zoom with f2.8 at 28mm through f3.5 in most of the midfield, and still a respectable f4.0 over about 70mm, and the low streetprice of well below 250 dollars, there is nothing to critique here in a bad way.
The Sigma 28-105 qualifies as a bargain of the year as far as I am concerned!
Strengths
What is in focus with this lens is very sharp! And at about f5.6 this lens is getting deeper and very crisp indeed! The whole thing also depends on distance. Read a book with a good DOF chapter, this is too much to write about here :)
FAST focusing in autofocus
I see no optical flaws to mention for a sub 2000 dollar piece. Nothing is perfect, and I am sure I can eventually find better, but this is one of the best lenses I have used.
Any geometry complaints would be nitpicking, as the wide end looks a little odd in any case, but for an APS sensor digital body that issue doesn't even arise, as the 28mm focal length translates to about a 42mm equivalent, a modest but still effective wide end, so any potential negligable distortions are nil.
For a film SLR or a full sized sensor cam the wide end would come to play much better of course. For wide angle shots I actually prefer a "funny" bulging psychedelic view, but this lens doesn't even deliver that. It's almost too d*mned straight for my taste (I'll learn to live with that...), so no worry about distortions.
As far as sharpness on the edges is concerned, I will have to report on that later after doing some more shooting, but so far not bad at all.
With my Pentax ist-DL I just made some shots in near darkness and the results blew me away. Very nice rendering,"bokeh" any way you want it, full subject isolation, or deep field, and the transition is nice looking.
And sharp - one needs to know what one is doing though ;)
This 28-105 is apparently not spec'd for digital, but works flawlessly with my Pentax ist-DL with the aperture ring in "auto". No complaints from me in digital operation!
Weaknesses
And here comes the ONE snag I see with this lens, that will surprise many:
The autofocus shaft causes friction on a manual focus body..
The rapid action autofocus gear (FAST focusing in autofocus) with the short throw on the front ring also makes the focus ring nearly impossible to turn and control smoothly on my old Ricoh and Pentax manual focus bodies. With the ist-DL it is NO problem, as the "manual" focus setting retracts the camera's shaft and makes for a cavity on top of which the lens shaft turns freely, and manual focus is ok, even though touchy. Then again with the DL the autofocus is neat and works just dandy.
No weakness really, except two small accessories:
The hood is a bit tricky to attach, very tight and notchy and could use a little better finish - then again, it is a "proper" hood, I have fiddled with others just as bad, and once on ... who cares.
The K-Mount mount cover is a sheer nuissance though - will need filing and fitting or a replacement, as I do not want plastic chafings from a 5 cent lid to get on my D-SLR sensor when I take the lens out and mount it!
Then again - the lens was cheap enough, and I'd rather have them cut a corner on a lid than on the glass and lens body!
Similar Products Used
Pentax "F" 50mm f1.7, Rikenon 55mm f2.2, Sears 28-70mm f3.5-4.5, Rikenon 28mm f2.8, Rikenon 135mm f2.8, Kalimar 70-210mm f4-5.6
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