Tale of two Sigma macros

[david_russell8]

<p>I got my K20D a few months ago thanks in part to advice on this forum (love it by the way!) and I'm looking at (just to play about with) buying one of the cheap Sigma macro zooms that seem to pop up on eBay quite a lot. The two of these seem to be 28-80mm and 28-90mm - both f3.5-5.6 and Aspherical Macro. Can anyone tell me what the difference between these two is (apart from the obvious focal length :P) and which of them is 'better'? (defined as 'better when used exclusively as a macro lens because I have two lovely Pentax kit zooms to do other stuff with' :P)</p>

[michael_elenko]

<p>David,<br>

First, what do you mean by "macro" shooting? Technically it means 1:1, very detailed insect body parts and the like. Informally a lot of people use the word "macro" to mean closeups of flowers or objects at about 1:2--1:4. To shoot 1:1 or even very good 1:2 macro requires a dedicated macro lens, like the Sigma 105mm. These are a few hundred bucks each.</p>

<p>I've never used or even seen in real life the two Sigma lenses you are curious about, but a quick look at reviews and the facts about both tell me that these are a) low-end zooms as in cheap and b) have fair closeup macro capability at best. In general you will get usable general shots out of either, especially if your shooting skills are good. For true macro work forget it; for closeups I would save my money for a true macro lens. Since you already have the Pentax kit lens, you are not purchasing any more optical improvements anyway, so why burden yourself with an additional lens?</p>

<p>ME</p>

[andrewg_ny]

<p>David, not finding much information about these lenses. I imagine it's because they aren't exactly 'enthusiast-grade' with crop-sensor digital SLRs so haven't been all that popular. However, I'd guess that either represent a pretty cost-effective way of getting an autofocus ~1:2 macro (assuming all versions of these have ~1:2 macro?), even if only f/5.6. I think I saw that the 28-90 has 1:2.3 at 90mm. <br>

I should mention that KEH appears to have the 28-80 in excellent condition for ~$25 and you can easily return it if you don't like it.</p>

[miserere_mei]

<p>The DA 18-55mm kit lens can do 1:3 "macro" at the 55mm end; can those Sigma's do better than 1:3? If you need anything more than that, then you're looking at a dedicated macro lens.</p>

[JDMvW]

<p>These are labeled "macro" like many other zooms, even some from the major manufacturers, but on these lenses the term that should be on the lens is "close focus". As Michael says, these are not true macro lenses in the sense that you can get the same size image on the sensor as you have in the real world (1:1 size ratio).<br>

For flowers and do-dads, these are fine, but if you mean to do buggies and such, you need a real macro lens of which there are many, often fairly inexpensive as well (as these things go). Probably the Sigmas are ok, but really old Sigmas sometimes have problems working with newer cameras, so if you decide to go for one, make sure you can return it if it doesn't work.</p>

[david_russell8]

<p>Knew there was something I'd missed out! Both of these are apparently 1:2, however if as suggested above the 28-90 is 1:2.3 then I'd guess the 28-80 would be 'better' as far as the word can be used in distinguishing two very entry-level items</p>

<blockquote>

<p>I should mention that KEH appears to have the 28-80 in excellent condition for ~$25 and you can easily return it if you don't like it.</p>

</blockquote>

<p>Thanks but I'm in the UK.</p>

<blockquote>

<p>For true macro work forget it; for closeups I would save my money for a true macro lens. Since you already have the Pentax kit lens, you are not purchasing any more optical improvements anyway, so why burden yourself with an additional lens?</p>

</blockquote>

<p>Hmm you might well be right - although most of my macro stuff would be in the "mucking about in the garden" sort of range from home, I probably would be happier waiting to get something specifically designed to do macro than another standard zoom (I love the kit lens to bits) which will only ever be used at its maximum focal length.</p>

[rparmar]

<p>An inexpensive option is the Vivitar/Cosina 100mm f/3.5 which does 1:2 or 1:1 with the included adapter, which is of high quality. I should sell mine, since I have a more expensive option. Except that it has produced <a href="http://www.flickr.com/photos/rparmar/tags/cosina100mm/">so many nice shots</a> for me, including this all-time favourite.<br>

<a href=" src="http://farm4.static.flickr.com/3083/2545644180_716652ba8b_o.jpg" alt="Gaze by Robin Parmar" /> </a></p>

[michael_kuhne]

<p>IMO, you are better off to just use your nice kit lens with its pretty close 1:3 capability than those cheap Sigmas. For a really good cheapie closeup lens, Robin is right. The same lens was also offered in a Pentax branded AF version, which should not cost much used.</p>

[david_russell8]

<blockquote>

<p>For a really good cheapie closeup lens, Robin is right. The same lens was also offered in a Pentax branded AF version, which should not cost much used.</p>

</blockquote>

<p>If I can find one of the Pentax ones over here then that sounds like a plan. I don't have the eyesight for MF to be honest :P</p>

[rparmar]

<blockquote>

<p>I don't have the eyesight for MF to be honest</p>

 

</blockquote>

<p>All macro work requires manual focus, to such an extent that I think auto-focus is a useless feature on a macro lens. (Though useful if you're using the same lens for non-macro work.)</p>

[paul_de_ley]

<p>I'll second that, for macro/closeup in the 1:2 range and above, autofocus is often more a nuisance than a boon. For relatively little money you could get an excellent used third-party MF macro lens (Tamron adaptall-2 90 f2.5 macro, Vivitar 90 f2.8 or f2.5 macro, etc). If you do nevertheless want AF for non-macro uses, Sigma's older versions of their AF 50 f2.8 macro are usually excellent value for money.</p>

[michael_kuhne]

<p>I agree generally regarding MF, but for subjects that move, I often use AF-C for close focus shots. Kind of a similar situation as when shooting telephoto for sports, where there's a shallow DOF and movement. </p>

[orly_andico]

<p>AF is quite useful on macro. As Michael points out, AF-C works fine for tiny adjustments when it's already locked on but the subject moves a tiny bit.</p>

<p>I have a 90mm f2.8 Manual Focus macro and a 100mm f2.8 AF and guess which one gets used all the time.. doesn't hurt that the Pentax D-FA is quite light.</p>

[snik75]

<p>For a mid range zoom with nice macro abillities, the Pentax F 35-70mm is a nice little zoom. It will only do 1:4, but has very good image quality in the "macro" range and for other uses as well - a step up from the kit lenses, I believe.</p>

<p>Or you can get a manual focus macro lens, which would likely be way better for macro shots.</p>