Weird bokeh on old Sigma lens

bieber · 23rd of December 2006 (Sat)

I just recently picked up a used EOS 20D, and for lenses I'm using the two that my grandfather used to use on an EOS film Rebel, a Canon 50mm f/1.8 and a Sigma 70-300mm f/4-5.6. I generally don't use the Sigma, because it's old, sort of sticky, operates weird (you extend or contract the lens by actually pulling the barrel forwards or backwards) and the iris is broken (you get an error message trying to shoot with the aperture anything other than wide open). Today, though, some herons were hanging out on my roof, and I decided to go ahead and pull it out of my closet and take some shots, and this is one that I got.

The thing I don't get is the bokeh. It seems almost...is swirly the right word? I got the same sort of thing happening on another image from a different angle, so I don't think it's just the tree behind it, and it can't be camera shake, because camera shake that extreme would have destroyed the subject. Is it something about the lens? I'm completely and utterly stumped by the effect, but it's something I'd very much like to be able to recreate later on, if I knew how...

RandyMays · 23rd of December 2006 (Sat)

It's the 5 blade vice 8 blade aperture. This produces what some consider poor bokeh.
Nice shot though !

bieber · 23rd of December 2006 (Sat)

Does that have any effect when the aperture is fully open? (It's the only way I can shoot). And I don't suppose there are any modern lenses that use the five blade? They all seem to be bragging about how many they can cram in there...

Savagebasher · 23rd of December 2006 (Sat)

Don't know about the bokeh, but I do know that the nifty fifty is still a 5 blade

RandyMays · 23rd of December 2006 (Sat)

Check out some of the reviews on the below site. I hop it sheds some light. I personally like the creamy smooth bokeh. http://www.the-digital-picture.com/

Bokeh:

jcw122 · 23rd of December 2006 (Sat)

It looks like the tree leaves were moving, which is why the bokeh (first pic) on the leaves is odd. Notice the bokeh of the trees in the far background (still first pic), it looks normal.

20droger · 23rd of December 2006 (Sat)

Was the tree wet (early morning dew or a wet day)? Water droplet relections/refractions often produce weird bokeh, especially if the tree was moving.

Was the tree backlit and moving? Sunlight through moving branches can also produce weird bokeh.

scokar · 24th of December 2006 (Sun)

The bird was about the break the sound barrier.

jcw122 · 24th of December 2006 (Sun)

Quote:

Originally Posted by scokar

The bird was about the break the sound barrier.

LMAO! It sorta does look like that too hahahah.

23rd of December 2006 (Sat)	#2
RandyMays Member Join Date: Feb 2006 Location: Nebraska Posts: 712 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens It's the 5 blade vice 8 blade aperture. This produces what some consider poor bokeh. Nice shot though ! __________________ Canon 40D, 5D MK II Speedlites 430EX & 580EX II Canon 70-200 f/2.8L (Non IS), Canon Extender EF 1.4 X II, Canon 400 f/5.6 L, Canon 100 f/2.8 Macro, Canon 24-70 f/2.8L

23rd of December 2006 (Sat)	#3
bieber Senior Member Join Date: Dec 2006 Location: Bradenton, FL Posts: 1,992 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens Does that have any effect when the aperture is fully open? (It's the only way I can shoot). And I don't suppose there are any modern lenses that use the five blade? They all seem to be bragging about how many they can cram in there...

23rd of December 2006 (Sat)	#4
Savagebasher Member Join Date: Aug 2006 Posts: 244 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens Don't know about the bokeh, but I do know that the nifty fifty is still a 5 blade

23rd of December 2006 (Sat)	#5
RandyMays Member Join Date: Feb 2006 Location: Nebraska Posts: 712 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens Check out some of the reviews on the below site. I hop it sheds some light. I personally like the creamy smooth bokeh. http://www.the-digital-picture.com/ Bokeh: __________________ Canon 40D, 5D MK II Speedlites 430EX & 580EX II Canon 70-200 f/2.8L (Non IS), Canon Extender EF 1.4 X II, Canon 400 f/5.6 L, Canon 100 f/2.8 Macro, Canon 24-70 f/2.8L Last edited by RandyMays : 23rd of December 2006 (Sat) at 22:56.

23rd of December 2006 (Sat)	#6
jcw122 Senior Member Join Date: Jul 2006 Location: West Chester, PA Posts: 1,933 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens It looks like the tree leaves were moving, which is why the bokeh (first pic) on the leaves is odd. Notice the bokeh of the trees in the far background (still first pic), it looks normal. __________________ "Ill show you."-John Hammond Gear List "YES! I AM INVINSIBLE!"-Boris

23rd of December 2006 (Sat)	#7
20droger Cream of the Crop Join Date: Dec 2006 Location: In a semi-civilized small town in southeastern Arizona. Posts: 12,881	Re: Weird bokeh on old Sigma lens Was the tree wet (early morning dew or a wet day)? Water droplet relections/refractions often produce weird bokeh, especially if the tree was moving. Was the tree backlit and moving? Sunlight through moving branches can also produce weird bokeh.

24th of December 2006 (Sun)	#8
scokar Member Join Date: Oct 2005 Posts: 953 IMAGE EDITING OK	Re: Weird bokeh on old Sigma lens The bird was about the break the sound barrier.

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