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Tordan58
30th May 2011, 08:43 AM
Hi all,

With the intention to improve the image yield with respect to sharpness I acquired a monopod some time ago and after a month use or so I was inclined to draw the conclusion that picture sharpness has increased. (With that I mean the percentage of sharp vs. non sharp).

Question is: how much?

So what I did last weekend was to perform the test procedure (http://www.wrotniak.net/photo/tech/is-m.html)that was pioneered (?) by J. Andrzej Wrotniak in 2009. Many of view are probably familiar with the test procedure, those who are not please have a look, it's really interesting and worthwhile reading.

The setup used in my test was the following:

Body: E620
Lens 1: 50-200 SWD @ 200 mm focal length
Lens 2: 50-300 with EC14 @ 420 mm focal length



Shooting conditions

Shots taken outdoors, EV 14 average (EV13-EV15 depending on clouds)
Subject: a piece of cardboard with text and some B/W graphics
Distance to subject: around 3 and 6.5 meters (for full frame shots)
Shutter speeds (shutter time priority)
200 mm: starting at 1/15 sec and decreasing 1EV down to to 1/1000 sec
420 mm: from 1/30 sec to 1/2000 sec
JPEG HQ
Shoot sequence: 10 frames. Camera can buffer 8 frames without delay, the last 2 frames will be somewhat delayed.
One sequence without IS, without monopod
One sequence with IS.1, without monopod
Ditto with monopod

Apertures and ISO ranges used:

50-200: F5.6 - F22 (could not avoid pictures at 1/15 to be overexposed +1EV)
70-300: F7.9 - F16 (could not avoid pictures at 1/2000 to be underexposed -1 EV)


In total were taken: 7*10*(1+1+1+1) = 280 pictures for each lens.

The assessment method I used was to look at each picture and compare the sharpness with what I know that the sensor and lenses can deliver under perfect conditions. Pictures were sorted into either of the following categories:

[* Sharp: close to best results that can be delivered. Slight blur is visible but noticeable only when viewed at 100% magnification, and hardly noticeable when displayed to fit computer screen (25% magnification)
Acceptable: blur noticeable at 100% but look sharp at 25% magnification
Bad: not meeting acceptable criteria


What I did was to log the results in XL sheets and have XL draw diagrams that I analyzed.

Diagrams showing the probability of a close to perfect shot for a given shutter speed. Four diagrams for each lens: IS.1 vs no IS, monopod vs. free hand.
Diagrams showing the probabilty of an acceptable shot


The results? I found that:

The benefit of IS vs IS.1 is somewhat less than 1 EV when used with the setup above
The benefit of monopod is around 1.5 EV
Above surprised me. I would have expected more benefit from the IS, and I would have expected the monopod to provide more benefits.

If anyone is interested I can share the data and graphs.



Post test discussion (feel free to fill in and provide critics and suggestions)

I took the pictures in sequences of 10, and not 10 single frames. My thought is that sequences would be what you do in the field when using a telephoto lens.
Wrotniak advocates 20 shots. I only took 10.
There was some variations in light, it was more or less cloudy. This could have affected the perception when looking at the pictures (higher or lower contrast)
I did not assess the pictures in true random order and this may have biased somewhat. To mitigate I ran the assessment repeated times to sort the pictures into (good, acceptable and bad) to avoid volatile evaluation critera to bias the result. Still, several shots were difficult to conclude which category they belong to.
The test should berhaps be run with another motif that allows easier assessment. Close inspection of sharpness B/W text is difficult and exhausting...

David Morison
30th May 2011, 09:15 AM
I bought a fairly heavy duty monopod a while ago for wildlife shots with the E5 and 300mm f2.8 + EC14 but I found that in general use it conferred no real advantage. Even with a monopod my setup was not rock-steady and I still felt a need to use IS1, but then it appeared that this introduced problems as it caused some blur. I now only use handheld with IS1 up to 1/640th and switch it off above that, it seems that leaving the IS to do it's job as it is designed to works for me. I now have a higher rate of "keepers" and feel that if the lighting situation is too poor then a tripod is the answer. Strangely I can still use IS1 when resting on a bird hide window shelf which is a much steadier situation than a monopod, don't know why but it works for me which is what counts.

David

Homer Simpson
30th May 2011, 10:21 AM
Wow!

Thats pretty impressive Tordan
I can't work out if you are ultra keen or have too much time on your hands;)

Interesting results

Just one thing I wonder if both you (& David) happen to have very good "hand held" technique that slightly skews the benefits of the monopod.

When I first bought the E520 the IS was a major attraction - now I'm less sure its such a big deal.

Warning Old git mode:
when I'm out and about I notice older photograghers (who probuably evolved from film cameras) have much better hand hold technique than young uns. Also I've never seen in a photo mag (past 3 years) and article about how to hand hold.

Tordan58
9th June 2011, 07:45 AM
Wow!

Thats pretty impressive Tordan
I can't work out if you are ultra keen or have too much time on your hands;)

Interesting results

Just one thing I wonder if both you (& David) happen to have very good "hand held" technique that slightly skews the benefits of the monopod.



Hi,

The test took about an hour to setup and run, and took an evening in front of the computer to digest.

I believe I have a decent "hand held" technique, in my case evolved during the late 70's, when Ektachrome 100 or 200 was the norm for color slides ...

/Tord

Ian
9th June 2011, 09:13 AM
I wouldn't have tested below f/8 as your results will be affected by diffraction softening.

Ian

Tordan58
9th June 2011, 10:10 PM
I wouldn't have tested below f/8 as your results will be affected by diffraction softening.

Ian
This actually struck my mind before running the test, but I decided to go for it anyhow. Since I exposed over a range of 9 EVs to be sure I covered the full range from 100% yield to 0% (1/2000 to 1/8 s) I had no other option (ISO adjustments would allow a range of 4 EV only with 1600 ISO upper limit, and once you are at the end of the ISO scale there is no other option than to reduce the aperture).

One alternative would have been to use (stacked) gray filters - which I don't have.

If you come up with an idea how to mitigate the risk of diffraction I could re-run the test and see if I get other results.

/Tord

PS the 70-300 with EC14 starts at f/7.9...

Tordan58
18th June 2011, 02:22 PM
Hi,

Attached to this post are the graphs showing the result of the test.

Cheers,
Tord

Ian
18th June 2011, 02:34 PM
This actually struck my mind before running the test, but I decided to go for it anyhow. Since I exposed over a range of 9 EVs to be sure I covered the full range from 100% yield to 0% (1/2000 to 1/8 s) I had no other option (ISO adjustments would allow a range of 4 EV only with 1600 ISO upper limit, and once you are at the end of the ISO scale there is no other option than to reduce the aperture).

One alternative would have been to use (stacked) gray filters - which I don't have.

If you come up with an idea how to mitigate the risk of diffraction I could re-run the test and see if I get other results.

/Tord

PS the 70-300 with EC14 starts at f/7.9...

I actually did a similar test a long time ago, see:

http://fourthirds-user.com/2007/07/olympus_e510_image_stabilisation_examined.php

Back then I ignored the diffraction factor :)

If I were to repeat the test today, I would stick to f/6.3 for peak resolution and vary the intensity of the lighting force an adjustment of the shutter speed.

Ian

Tordan58
18th June 2011, 02:43 PM
Thanks for sharing,

It seems that you used SW to analyze the results, rather than an subjective inspection of sharpness. Whan SW did you use, if I may ask?

I might revisit the test and figure out how to eliminate the risk of diffraction.

/Tord

PS

Spybot Search and Destroy reports that your article has links to malicious SW. Thought you wanted to know.

Ian
18th June 2011, 05:15 PM
Thanks for sharing,

It seems that you used SW to analyze the results, rather than an subjective inspection of sharpness. Whan SW did you use, if I may ask?

I might revisit the test and figure out how to eliminate the risk of diffraction.

/Tord

PS

Spybot Search and Destroy reports that your article has links to malicious SW. Thought you wanted to know.

I used DxO Analyzer, which is a commercial image analysis software suite from the same people that produce DxO Optics Pro. It's explained in the article :)

Can you email me the data concerining the dodgy links - it could be some unwanted ad banners we occasionally get, but to stop them I need to know what they are!

Thanks,

Ian

forum-admin AT e-group.uk.net

Tordan58
18th June 2011, 06:53 PM
Hi,

There are two links in the article that appear as providing information about the SW used but they pretend how to get a US green card and redirect you to www.usagc.org/....

The malicious resource is reported under teh name "Yeke"

/Tord

Tordan58
18th June 2011, 07:00 PM
Ian,

Actually I found four links after closer inspection. I have reproduced the body text and underlined the link below


The Olympus system is interesting because it uses in-house Supersonic Wave Drive (SWD) technology

The DXO system uses a special test target that the Analyzer software

can intelligently analyse to provide information

but even at 1/4 sec you are likely to get better results than hand held