Pan 35-100/2.8 and Oly 75/1.8

Started Dec 23, 2012 | Discussions thread
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Vittorio Fracassi
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Pan 35-100/2.8 and Oly 75/1.8
Dec 23, 2012

When I sold my 4 year old Canon 200/2L IS to a well known shop in Torino the deal  was closed with a barter: a new Pan 12-35/2,8, a new Pan 35-100/2.8, and cash.    I wasn’t really hungry for the two Pan HQ zooms but the proposal was the best I had at hand, so I closed the deal, taking the 12-35/2.8 which pushed my 12/2 out of the bag (yes, my final controversial decision was to sell it) and the cash, waiting for the 35-100/2.8 to be delivered.

It finally arrived so I decided to put it through some of my empirical standard tests as I do with every new lens, to find out if it’s a good copy or not, in this case using the 75/1.8 as benchmark, (as I used the 12/2 for the tests on the 12-35/2.8).   The E-M5 being the camera body.   Not aiming to decide if the 35-100/2.8 was going to push the 75/1.8 out of the bag, but not discarding the possibility.

My indoor subject setup had mid/low illumination, 4.5m subject to camera distance, stationary objects (books on a shelf).  My aim was to evaluate microcontrast, efficiency of Image Stabiliser, ease of focussing (in particular fine Manual Focussing).      I took no less than 3 captures RAW for every setting and selected the more representative one.   Taken handheld and using AF with smallest area + fine Manual Focussing at x14 zoom, thus reducing the optical significance but including practical elements like the efficiency of the IBIS and the influence it has in keeping the subject still at 150mm equivalent FF focal length when manually focussing through the EVF.     Significance and reliability of my findings is a bit shaky, but the procedure gives indications with regards to field conditions,  in Portaiture for example, and will condition my choices in future.

Before showing images let me put down two observations:

1-      Comparing microcontrast and colour rendition at F2.8,  with IBIS (1) ON set at 75mm, OIS for the 35-100 OFF, 1/8sec anti-shock shutter lag, same ISO and exposure time, the Pan 35-100/2.8 delivers images just less sharp than those of the Oly 75/1.8, and just looses for the cleaner colours with slightly better transitions of the Oly 75/1.8

2-      Doing the same comparison but using the max aperture advantage of the 75/1.8,   setting it at F1.8, and as a consequence benefiting from a lower  ISO to 640 instead of 800 and shorter exposure time from 1/160 to 1/320sec, microcontrast and colour rendition are just  better than those obtained by the 35-100/2.8, see images below of a 100% detail crop, (which I consider extremely sharp and free of Noise considering they are the default JPEGs from RAW conversion with zero PP).



Pic. 1  Setup and Target  (following pics are 100% crops corresponding to the target)

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Pic. 2   35-100/2.8 on E-M5, to compare with 75/1.8 on E-M5, F2.8

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Pic. 3   75/1.8 on E-M5, to compare with Pic.2 above

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At this point whoever reads this post will say: “is that all? Many reviews say that and in a better way...”, but during my testing I found more correlated data which may turn out useful, at least to me.

3-     The behaviour of IBIS and OIS.  Comparing the sharpness of the images in relation to these Stabilisers, each excluding the other on the Pan 35-100 and IBIS on the Oly 75/1.8, the IBIS wins,  just marginally over OIS.  In particular if the right focal length, in this case of 75mm is set in the menu.

4-     Another interesting point on IBIS and OIS.   Both systems, and IBIS just better then OIS deliver outstandingly sharp images of still subjects at exposure times of 2/Fn.  In other words 1/40th sec.   But then things get a little worse for both between 1/80th and 1/160th sec , only to become really good again at 1/200th, fantastic at 1/320th and shorter, where IBIS and OIS are not necessary any more for the 75mm focal length.



Pic.4   the OIS is not helping the 35-100/2.8 at the critical exposure time (a little blurred)

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Pic. 5   well  tuned IBIS works better on the 35-100/2.8 at critical exposure time, but still not perfect

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Interesting to note that one can do nothing but avoid to use the 35-100/2.8 with the OIS on,  in the 1/80thto 1/160th interval by playing with the ISO, either lowering it if the subject is stationary and gaining the reduction of Noise,  or by increasing it to obtain exposures higher than 1/200thto freeze less stationary subjects and take some Noise, which by the way is really well controlled by the E-M5 even at zero, in camera, NR.   IBIS at these critical settings performs better than OIS, in particular if tuned on the focal length, but the result is still not optimal with the 35-100/2.8 and just acceptable with the 75/1.8.

5-      I also played around a bit with anti-shock delay at exposure times ranging from 1/40th to 1/200th sec comparing 1/2, 1/4th, 1/8th and zero secs.   1/4thand 1/8thgave the least blur, note that at 1/2 sec and longer the blackout in the EVF is so evident that I fear it induces a reaction in the photographer which may cause camera shake.

6-      On the 35-100/2.8 AF is very fast.    In fine tuning of AF by Manual Focussing the OIS gives a rock steady image in the EVF at x 14zoom, and it’s easier to really focus accurately than with IBIS which shakes.

7-      Bokeh was not investigated but a few captures were made to identify the difference in blur at F2.8 and F1.8 of details  about 30cm behind the target (set at 4.5m from the camera), with the 75/1.8.    There is a marked enough difference.     The DOF calculator at http://www.dpreview.com/learn/?/Glossary/Optical/Depth_of_Field_01.htm       gives for a 4/3” sensor,  lens focal length of 70mm, F1.8, subject distance of 4m, a total DOF of 20cm and at F2.8 a total DOF of 31cm, confirming what we see.



Pic. 6   observe the vertical letters in the top right corner which are readable at F2.8 (taken with 75/1.8) 

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Pic. 7   observe the letters in top right corner which are blurred at F1.8 (with 75/1.8)

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the letters "RU O181" appear readable at F2.8 and still readable but blurred at F1.8.

8-      One more remark concerning zooming and focus.  I had some Canon zooms in the past years and once the focus was set zooming in or out maintained the focus, whilst the 35-100 shifts the focus point during zooming and refocusing is mandatory.   Strange, it may lead to some unwanted misfocussing if one decides to zoom at the last second without releasing the shutter button and refocusing.

So my first impressions are that at the focal length of 75mm on the E-M5:

  • the microcontrast of pics taken with this zoom is very very good,
  • it’s preferable to use IBIS rather than OIS,
  • the exposure times from 1/80 th to 1/160th sec are at risk of blur so better avoid them,
  • manual focussing at max zoom is a pleasure to use with OIS, and
  • to get the best out of it when mounted on the E-M5 the camera has to be carefully set with respect to anti-shock and IBIS tuning.   

The max aperture of the 35-100/2.8 together with the low Noise of the E-M5 at higher ISOs (tried 1600) will guarantee a good performance in dim light but low DOF will be attained only at the very long end of the zoom so it will not be so good for isolating subjects, the 75/1.8 being more indicated.   In my case the 35-100/2.8 will not substitute the 75/1.8 but for many photographers the need for the 75/1.8 may not be felt.

Please, if you did not fall asleep during the reading of this lengthy piece, comment with possibly your experience with this lens or for any other reason,

Regards,  Vittorio

PS. excuses for not showing all the pictures connected with my tentative statements, this was done not to take too much space in this Forum, I can upload them on request.

 Vittorio Fracassi's gear list:Vittorio Fracassi's gear list
Panasonic Lumix DMC-GH1 Canon EOS 7D Panasonic Lumix DMC-GX1 Olympus OM-D E-M5 Canon EF 35mm f/1.4L USM +10 more
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