Bokeh: R1 vs Sigma 18-125mm

Took 2 pics in my bedroom yesterday to compare the bokeh between R1 and my Canon 350D/Sigma 18-125mm f3.5-5.6. Focus was on the camcorder's flip open LCD "Canon" logo.

Observations:
1. Just love the R1 bokeh! Mr Donald is more "bokeh" in R1 shot than Sigma shot.

2. The R1 color is much more accurate to the warm florescent lighting in my bedroom. The Sigma color is too cool.

3. R1 pic seems brighter even though slightly faster shuttle and same ISO200 rating. Strange?

Details: Off shoe bounce flash using Sunpak 383 manual. Pictures shot at cam's full resolution, ISO200, manual mode using f4.0 and 1/100 (Sigma) and 1/125 (R1). No post processing. WB are manual calibrated for both cam.

Canon 350D, Sigma 18-125mm F3.5-5.6, 1/100, F4, ISO200



Sony R1, 1/125, F4, ISO200



Andy

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OLY 2020 > PANASONIC FZ1 > FUJI F10 > CANON 350D > SONY R1

Please define "bokeh" for me so I know what to look for.

Also, how do you like the 383 flash with R1? I do not do much flash photography, but I'm looking for somthing inexpensive for flash fill-in work. Several STFers seem to use the 383.

There is quite a marked difference between the shots, did you process them differently? and/or shoot in RAW?

P.S The R1 shots looks much better but I'm biased :-D
--

Paul
:::: http://www.aipix.co.uk :::
http://www.flickr.com/photos/digipixuk/
.::Sony R1 - What a camera!::.
.::Sony F828 - mmm the swivel!::.

I'm mainly seeing a difference in focal length, which is giving you shallower DOF in the R1 shot. I don't see much in these shots that would let you draw any conclusions about the bokeh from either lens.

BTW, the 18-125 is an annoying lens to test because the focal lengths reported to the camera change is large jumps. I've also found that the lens will tend to underexpose in some conditions, suggesting that the aperture mechanism also works in coarse increments.

IMO, the bokeh from the 18-125 isn't too bad when it is stopped down a bit but has an ugly, smudgy quality close to wide open. Here's an example with decent bokeh, IMO:

http://www.pbase.com/parr/image/34948562

Here are two versions of essentialy the same shot a different f/stops. Notice how the wider aperture has that smudgy look:

Stopped down:

http://www.pbase.com/parr/image/34728825

Opened up:

http://www.pbase.com/parr/image/34728827

--
Ron Parr
Digital Photography FAQ: http://www.cs.duke.edu/~parr/photography/faq.html
Gallery: http://www.pbase.com/parr/

Don't try and kid yourself, number1 is far far sharper and looks far nicer, the second looks soft and mushy!

That was the purpose of the test... you didn't look good though: check out the manual focus ring on the camcorder: the second photo shows the little ribs in full detail, in the first photo you can't even see them!
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oVan - http://ovan.be/

Gerry,

Straight from wikipedia: "Bokeh (from the Japanese boke ぼけ, "blur"[1]) is a photographic term describing the subjective aesthetic qualities of out-of-focus areas in an image produced by a camera lens. For example, causing an out-of-focus background image may reduce distractions and emphasize the primary subject. Although difficult to quantify, and hence open to debate, some lenses are believed to enhance overall image quality by producing more subjectively pleasing out-of-focus areas (bokeh)."

Bokeh at f2.8 will be even more pronounced than f4. Choice of f4 was very much limited by the focal length I used for the shot.

I have found indoor flash pic with 383 to be very pleasing. I usually use it in manual setting using the R1 "zebra" feature to get the best aperture/shuttle setting. I will highly recommend 383 flash as an inexpensive option the the dedicated Sony flash.

Andy

Gerry Pasternack said:

Please define "bokeh" for me so I know what to look for.

Also, how do you like the 383 flash with R1? I do not do much
flash photography, but I'm looking for somthing inexpensive for
flash fill-in work. Several STFers seem to use the 383.
--

Click to expand...

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OLY 2020 > PANASONIC FZ1 > FUJI F10 > CANON 350D > SONY R1

Ron,

Thanks for sharing about the underexposure problem with Sigma. That could be the explanation why the Sigma shot seems dimmer and R1 shot brighter.

Yes, the focal lengths are slightly different and the resulting difference in DOF could account for the different blurness in background. A better test would have been to control the focal lengths. But I will not be able to repeat this test again as I sold my 350D yesterday!

Andy

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OLY 2020 > PANASONIC FZ1 > FUJI F10 > CANON 350D > SONY R1

No post processing. These are jpeg's straight from the cam.

Andy
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OLY 2020 > PANASONIC FZ1 > FUJI F10 > CANON 350D > SONY R1

oVan,

You made a very good observation about the lens cap. The R1 pic shows more details. Can this be due to R1's higher 10M resolution or a sharper lens or both?

Here are the 100% crops for comparison.

350D Sigma



R1



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OLY 2020 > PANASONIC FZ1 > FUJI F10 > CANON 350D > SONY R1

AndyChiang said:

Took 2 pics in my bedroom yesterday to compare the bokeh between R1

Click to expand...

This a difference in DOF, not bokeh. The backgrounds look the same, just one is sharper than the other. Bokeh is more about the shapes and transitions in out of focus background (see Ron's examples).
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Misha

AndyChiang said:

You made a very good observation about the lens cap. The R1 pic
shows more details. Can this be due to R1's higher 10M resolution
or a sharper lens or both?

Click to expand...

I think the 350D is focused on the back of the camera. I think the R1 is focused on the front of the camera. Not only does this explain the difficulty seeing the little grooves around the lens cover, it also explains somewhat why the background is more OOF in the R1 pic.

In the future, you should control not only the FL, but also the focal point. ;-)

--
Charlie Davis
Nikon 5700 & Sony R1
CATS #25
PAS Scribe @ http://www.here-ugo.com/PAS_List.htm
HomePage: http://www.1derful.info
'I brake for pixels...'

Depth of field is the section of the depth of the image that will be in focus.

Bokeh is the aesthetic quality of the out-of-focus area - is it smooth, grainy, showing the iris, etc?

You have shown two photos that have radically different depth of field. There's not enough background, nor is the camcorder isolated enough from the background to determine the quality of bokeh of either camera.

There is no "better" or "worse" DOF. It is a formula. At a given focal length, circle of confusion, and subject distance, they will have the -identical- DOF, regardless of quality.

Plus, I think you are unintentionally shooting at two very, very different focal lengths.

DOF is determined by the REAL focal length, not the 35mm equivalent.

Check the front of the R1.
The -real- focal length is 71.5 mm, effective 120 mm
The -real- focal length of the Sigma is 125mm, effective 200mm on the Canon.

Your comparison, unfortunately, tells you nothing. In any DOF formula, the R1 at full zoom will automatically have much greater DOF (the lower the focal distance, the greater the DOF) than the Sigma at full zoom.

Unless you've compensated for the FOV crop factor, I'm afraid you've been comparing apples and oranges.

--
=~ AAK - http://www.aakatz.com
=~ Author of the H-Series White Paper
=~ http://www.aakatz.com/h1whitepaper

and add the tiny difference in the crop factor into the mix as well, whcih makes f4 on the R1 = f4.6 on the XT... and the difference of in-camera jpeg sharpening level... too bad you sold the XT, Andy... would've been an interesting comparison, preferably done in raw, though I suspect bokeh would be ok in both cases (bokeh being subjective anyways)
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Martin

f4 on the XT = f4.6 on R1... and that f4.6 is wrong too... more like f4.3
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Martin

Crop factor should have no effect whatsoever on aperture that I know of.

But it has a huge effect on focal distance.

The "equivalent" focal distance between the two is:

R1, 120mm
Sigma: 200 mm

Don't forget the R1 lens is actually 71.5 mm, whereas the sigma is a "true" 125mm.

He's comparing a 1.5 mm lens to a 125 mm lens, since -real- focal length is used in the DOF calculations

It would have a huge impact on DOF.

--
=~ AAK - http://www.aakatz.com
=~ Author of the H-Series White Paper
=~ http://www.aakatz.com/h1whitepaper

You're right Alan, I don't know what was going on in my head to add aperture into the mix. But the focal length he had each lens set to is unknown (unless I've misread)... I'm assuming he set both to within range of each other, each one somewhere between 28mm and 120mm (28mm being the Sigma at the widest @ 1.6x crop?
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Martin

That may very well be the case, but that doesn't explain why the focus ring has no detail in the first photo. I say it is merely because of less resolution and more compression/noise reduction. Other lines are in focus at that same distance, check the lens cap. We are definitely talking about loss of detail here...IMHO!
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oVan - http://ovan.be/

oVan, it's two different focus points for sure. Have a look at the camcorder eyepiece section, where the XT is in focus while the R1 isn't. The DOF is very shallow in these shots and the focal length is at the longer end, so it's quite usual that things go quickly goes OOF in both the XT and R1 images.
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Martin

the focus is out of focus in the 1st picture, the focus is towards the eyepiece at the rear