Originally posted by Setter Dog There are plenty of Sigmas available at very good prices but they are described in various ways, DG, Macro, APO, etc. I can't find any information on what the differences are. The specs on all look exactly the same.
Sigma's terms:
DG - lens designed for digital cameras. Has better coatings.
Some Sigma lenses are designated "DG". What does this mean? | Sigma Corporation of America Macro - Strictly this means lenses that can focus very close to the subject, so that the image produced on the sensor is the same size as the subject (1:1) or even greater. But the term is bandied around to describe various lenses that can take close focus photos. The current Sigma 70-300 (
Sigma 70-300mm F4-5.6 APO DG Macro Lens Reviews - Sigma Lenses - Pentax Lens Review Database ) can produce images to a ratio of 1:2. That is very good for a zoom lens. Of course the image quality won't be nearly as good as from a dedicated macro lens (or, I suspect, from the Pentax 55-300 with a Raynox diopter - see below).
APO - Sigma says this: "
Apochromatic lenses are telephoto and telezoom type lenses which use special optical designs and optical materials (SLD or ELD glass) to improve their performance. The result is images which have greater contrast, sharpness and color definition than a comparable non-APO type lens . All Sigma apochromatic lenses are identified by the APO designation in their descriptions."
Check the PF user reviews for the various models:
Sigma Lenses for Pentax: Current Zoom Lenses - Pentax Lens Review Database - current models
Sigma Lenses for Pentax: Legacy Zoom Lenses - Pentax Lens Review Database - legacy models
See here for the current model Tamron 70-300:
https://www.pentaxforums.com/userreviews/sigma-lenses-for-pentax-zooms-c74.html Originally posted by boriscleto If you are looking for a lens to use at 300mm consider the DA L 55-300. These are usually available for less than $200 and are better at 300 than any of the Sigma or Tamrons.
+1. The Pentax 55-300 comes in 3 versions: DA-L, DA and DA WR. They are optically identical. Only the DA WR is available new.
The DA-L is one of the all time great lens bargains at around $US150 second-hand (DA version usually goes for about $50-70 more). The DA-L differs from the other two versions in that it has a plastic mount (not metal), doesn't come with a lens hood and doesn't have Quick Shift (manual focus override), but these limitations are minor. The plastic mount has proven quite durable. You can buy a lens hood for $5 on ebay. QuickShift is a nice feature (useful if you use back-button auto-focus), but not essential (the Sigma and Tamron xx-300mm lenses don't have it anyway).
If you would like to take macro or very close shots of flowers, insects and all manner of other small things without spending the extra on a specialist macro lens, the 55-300 pairs well with a Raynox 150 diopter (about $80:
DCR-150 Macro conversion lens for D-SLR camera). The Raynox just attaches to the end of the lens. People have got great results with the Raynox:
https://www.pentaxforums.com/forums/122-lens-clubs/74221-raynox-macro-club.html
The Pentax is sharp (for a consumer zoom), lightweight, compact, handles well and produces very good colours. Not particularly susceptible to chromatic aberrations (the Tamron is notorious for purple fringing). On the K-3, it will benefit from the faster AF drive. If you shoot jpg only, the camera can do in-body correction of distortion, vignetting etc (this only works with Pentax lenses).
Last edited by Des; 03-28-2015 at 05:15 PM.