Pentax M 100mm vs 120mm vs 135 F3.5

[tim_drake]

<p>I have read complaints that the 135mm F3.5 doesn't focus close enough. Just how close do these three lenses focus? Does anybody know how many aperture blades each lens has? Does anybody have a favorite of the three as far as image quality? Loads of Thanks, TD</p>

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[stemked]

<p>I think you can find that info on Boz's site:<br>

http://kmp.bdimitrov.de/</p>

[pbarnes]

<p>Tim, all you will ever need to know about the specs of Pentax lenses: http://www.bdimitrov.de/kmp/</p>

<p>You will need to be a bit more specific about the lenses you are asking questions about here, by Pentax M 100mm do you mean an M series lens, or is the M for Macro? </p>

<p>I have the M series 135/3.5 (not the K 135/3.5 which is a different lens) and its image quality is very good. For the price you can get them for, I think they are exceptional value. I just bought an M series 100mm Macro because the 135mm does not focus closer than 1.5m, but not able to compare image quality yet.</p>

[bkpix]

<p>M 135/3.5: 1.5 meters. Neat, sharp, compact and cheap. And has a built-in hood.</p>

[andrewg_ny]

<p>Honestly between them, I pick based on focal length. The most appealing package to me is the M120/2.8. Has slightly shorter min focus of 1.2m, 8 aperture blades, and is a very useful length for close-ups. It's also a smidge faster. For whatever reason, the 135 length is much more common than either the 100 or 120 on the used market. I have a few theories on this. 100/2.8 isn't different enough from the popular 85mm which is usually a stop or more faster. And 100 is a common length for macro lenses, so many who want 100mm go for the macro instead. I have a few of these but haven't used any enough to generate strong opinions about their optics which all seem pretty good so far--so my preference is mostly based on the package--physical attributes & specs.</p>

<p>Incidentally, the M75-150/4 zoom is also inexpensive, covers all these lengths, and seems pretty good. Min focus 1.2m.</p>

[tim_drake]

<p>Thanks for the replies and the links. I was referring to the M series lenses, not the macro. So the 120 has 8 aperture blades, how about the 100mm and the 135mm? Thanks.</p>

[andrewg_ny]

<p>Tim, specs like that are all at Boj's site that Douglas & Peter provided links to (it's the same site). Believe 135 has 8 and 100 6 but I don't own a 100.</p>

[miserere_mei]

<p>Andrew, and just for fun, there was also a K 105mm f/2.8 :-)</p>

<p>I owned an SMC-M 100mm f/2.8 for a short while (I got it as collateral baggage in an eBay kit sale) and I loved how small it was. I saw no fault with the IQ.</p>

<p>I will also give a thumbs up for the SMC-M 75-150mm f/4. Not only is it optically good (sharp from wide open), it's also very small for a zoom.</p>

[andrewg_ny]

<p>Yes, though my observation about the relative rareness of M100 holds true with the K105 as well--for whatever reason, either people hold onto them or they were less popular to begin with. I think 85mm and 135mm seem to be the most common.</p>

[jtk]

<p>I've got an M 85.2...focuses to about 2.5'. Significantly lower contrast than newer lenses, therefore great with low light situations. Low contrast might be a concern for a JPEGGER/non-printer, but its great with RAW and Lightroom.<br>

f2 at this focal length is the reason I bought it. Easy to manually focus on k20d in low light. Beautiful construction. The plastic Pentax shade is junque so I use a rubber one...49mm of course, so the collapsible 35/2.5 and 70/2.4 would be perfect if not otherwise occupied.</p>

[tim_drake]

<p>I gave up on finding a K105. The M120 seems to be about 5 times the price of the M135 F3.5. I am actually looking to use this lens on a film camera only. I would be interested in hearing more thumbs up on the M75-150mm zoom. Thanks, TD</p>