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07-10-2010, 03:58 PM   #1
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M 100mm/2.8 vs various portrait lenses ( 70mm/2.4 85mm/2 ... )

Actually it is quite different lens, but what makes me compare it is it's price, fast aperture and nearest focal length with mentioned properties. I't also quite compact.

It seems that this lens gets comparatively little exposure. I could find much less samples than with others. Still, while looking at them, the only major difference is bokeh.

As far as i could tell from the samples bokeh seemed to me quite busy. The problem - M lens doesn't report aperture, so my question would be:
Is the bokeh rather harsh with fully open (round) aperture or only when you start to stop down (aperture gets hexagon shape).

I've had DA70/2.4 and now i have F50/1.7, but sometimes i feel like i need a little bit more of a reach.
Main use would be low light head only portraits with good pop and nice bokeh at "comfortable" working distance.
I might even get back to DA70 at some point (very unlikely), but currently i need something very economic.

Since it's not from the cheapest primes either, is it worth the money for such application? Or i should save a bit and get something more suitable.

Thank you.

07-10-2010, 04:10 PM   #2
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I did a comparison of slightly longer portrait lenses, 3 of them which I own, and posted the results.

the 3 were

SMC Takumar 135 F3.5, Tele-Lentar 135 F2.8 preset, and a Rikenon 135 F2.8 M42 lens.

I deliberately omitted my smc pentax 135 F2.5 because that lens blows everything away, but I wanted to see the difference between M42 lenses.

The results were posted I think in the 135mm club. What was interesting is that that the tele lentar preset, seemed to have less DOF, and more separation of infocus and out of focus than the other 2 lenses. SHarpness and color rendition were equal to the SMC Tak. The rikenon had a color shoft that I did not prefer as much.

You might want to look at a 135 as well.

As for 100mm is lenses, I have an SMC Pentax 105 which I like, and am looking a=for a 105 for my M42 kit, but have decied to go with a preset, and round aperture all the way down, like my 135 tele lentar. the reason is I want something different than the pentax for my M42 set
07-10-2010, 04:32 PM   #3
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At 135mm i have Jupiter 37A 135/3.5. A decent lens and nice for portraits because of its large (was it 20?) aperture leaf count. But thats way too long for the application. 100mm is already a fair deviation from the 70..85mm range.

I've had a look at Jupiter 85/2, but it does not deliver the quality i'm after.

Btw 105/2.8 tak. can be had even cheaper than M100/2.8, but its told to be much softer and lacks color and contrast because its not SMC (at least the ones on the auction site).
07-10-2010, 06:46 PM   #4
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I have the M100/2.8 but seldom use it for portraits, only because it's rather long for that on APS-C. It is my single favorite lens for concert photography, though. I shoot wide open all the time in that setting, but these are not shots were the bokeh is much of an element. I did a searhc of my database to find portraits shot with the 100, and they are almost all outdoors (to be expected given the focal length) and probably stopped down. Bokeh is indeed busy. Most of the shots I have - concerts, or the couple of indoor portraits - either have backgrounds that disappear entirely into shadows, or have relatively featureless backgrounds, or are still pretty much in focus and haven't had a chance to "get busy". These are only examples I could find offhand that show anything about bokeh wide open:




Here's a typical exmaple that I think doesn't say much about bokeh, although I suppose it suggests that in some cases, it won't be an issue one way or another:



07-10-2010, 06:54 PM   #5
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I like the 100 and 135 mm focal lengths for outdoor portraits, and head and shoulder shots. They are definitely too long for idoor shots, where really even an 85 is a bit long at times.

The other thing to consider is that while 85mm was the real portrait lens for film, a 50mm today has similar field of view when used on teh crop sensor, and you have great options in the 50-55mm range including a lot of F1.4 lenses that give great isolation of the subject due to the shallow DOF
07-11-2010, 02:14 AM   #6
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Thanks for the samples Marc. I think i shall stick to my 50/1.7 then. At least until i have a chance to get something nice around 70..85mm.

The problem with 50mm is if you need to get head only portrait you need to be less than 1 meter close. When taking pictures in some event, this might be disturbing to some people.

P.S. Super takumar 105/2.8 has quite creamy bokeh:
http://www.flickr.com/search/?s=int&w=all&q=takumar+105+2.8&m=text#page=14

Last edited by ytterbium; 07-11-2010 at 02:39 AM.
07-11-2010, 10:04 AM   #7
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A fast 50mm should be ideal for portraits with your DSLR.

Chris
07-11-2010, 11:17 AM   #8
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QuoteOriginally posted by ChrisPlatt Quote
A fast 50mm should be ideal for portraits with your DSLR.

Chris
No offense, but replies like this often makes me think that 50% of users don't read the posts at all or read only few lines, before they fire away something meaningless just to keep their post count ticking.
This way multi page threads are created where it is nearly impossible to collect any useful information.

As i was saying before i already have a fast F50/1.7. Besides that i have TAK55/1.8 and in the past i've owned or tried M50/1.7, M50/1.4, 44m-58/2, 61L/Z 50/2.8, 50-2 50/3.5, 70/2.4Ltd and observed that at ~50mm you end up being uncomfortably and confusingly close for a subject who's not used to cameras and big lenses when you're trying to get a head-only portrait.

At the same time with 70/2.4, 50-200, Sigma 70-300, i've found out that 70..100mm is perfect focal length for such images indoors. I'd say even if my 70/2.4 was optically perfect it was a bit too short. Zooms - quite too slow for nice subject separation (especially indoors with lots of distractions and no chance to get far-away background).
Since i rarely do this kind of photography, the 70/2.4 was sitting on the shelf too much. Still i'd like to purchase something with similar qualities, but much more economical.

Now back to your advice. Have you used M100/2.8 or Super-Takumar 105/2.8. Do they justify their currently quite elevated price and deliver quality evidently superior to zooms, while still being as compact (as 50-200) or smaller/lighter?


Last edited by ytterbium; 07-11-2010 at 11:32 AM.
09-26-2010, 10:24 AM   #9
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Now that i've had 100/2.8 for some time i can draw some conclusions.

First of all the lens seems to be much better than expected.

Before i red some reviews that this lens doesn't have the crazy sharpness of M's. I think it's false. It might seems so because at this focal length the DOF is a lot thinner even at smaller apertures.
This also means that f2.8 @ 100mm gives enough subject separation, if not even more than 2.4@70mm.

The colour is rendered very well - as good as my 70ltd. I think M50/1.7 had some odd cast and M28 was slightly dull, this lens has very faithful and rich colours.
The coatings are excellent. In a direct sun back-lit shot i got no flaring or colour casts, just a tiny loss of contrast.

Now the bokeh - here some differences can be observed. 70LTD had more gradual highlight patches. This lens at open renders highlights as circles, that makes them more noticeable and not so well blended in background blur.

Some images, no pp except resize, unless otherwise specified:



1.


2.


3. Levels adjusted (was overexposed).


4.




5. flickr does remove some detail from 100% crops.

Some more at here:
SMC Pentax-M 100mm f/2.8 NON-Macro samples - a set on Flickr
09-27-2010, 05:52 AM   #10
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Nice shots. I'll disagree with my esteemed fellow forum members a tad and say that to me, your 50 is not a good substitute for the 100 on film. I find that the FA77 gives me more of what I needed from that FL on film. By the math, it is a tad longer, but it works.

I've looked into the M100/2.8 several times, but since I need a macro at that FL and speed, I doubt I'll spring for another 100mm.
09-27-2010, 06:31 AM   #11
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QuoteOriginally posted by GeneV Quote
Nice shots.

I've looked into the M100/2.8 several times, but since I need a macro at that FL and speed, I doubt I'll spring for another 100mm.
Again, nice images.

Consider the DFA 100/2.8 Macro WR. It is soooo... sweet. I hope you get the chance to examine it, too. Worth every penny when paired to a K-7, IMHO.

Cheers...
09-27-2010, 09:24 PM   #12
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QuoteOriginally posted by Michaelina2 Quote
Again, nice images.

Consider the DFA 100/2.8 Macro WR. It is soooo... sweet. I hope you get the chance to examine it, too. Worth every penny when paired to a K-7, IMHO.

Cheers...
I'd love to have that lens if it only had an aperture ring. I still have more film bodies than DSLRs (barely) and two of my favorites need aperture rings.
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