File :-(, x, )
Triangle bokeh Anonymous
Is anyone else bothered by the triangle out of focus highlights on the Sigma 30mm f/1.4?

It's a lovely lens for all it is. No one else bothered to make a modern normal prime for crop and a 1.4 at that.

I'm willing to forgive the less than stellar edges wide open but the triangle bokeh is not to my liking.
EXIF data available. Clickhereto show/hide.
Camera-Specific Properties:Equipment MakeCanonCamera ModelCanon EOS DIGITAL REBEL XTCamera SoftwareDigital Photo ProfessionalImage-Specific Properties:Pixel CompositionRGBImage OrientationTop, Left-HandHorizontal Resolution350 dpiVertical Resolution350 dpiImage Created2007:07:07 21:07:13Exposure Time1/50 secF-Numberf/1.4Exposure ProgramManualISO Speed Rating800Lens Aperturef/1.4Exposure Bias0 EVFlashNo Flash, CompulsoryFocal Length30.00 mmColor Space InformationsRGBImage Width1050Image Height700RenderingNormalExposure ModeManualWhite BalanceManualScene Capture TypeStandard
>> Depressed Cheesecake !wFh1Fw9wBU
Where do you see triangle bokeh? It looks like a rolled up condom.
>> The Pentacon !!XucVlAk1mCB
I think you're looking for things to complain about. It looks fine.
>> Anonymous
Right edge, near the bikes.
>> Anonymous
I don't know if I'd call them "triangles" but there is significant deformation in the highlights.

I'm glad I don't have one.
>> Anonymous
Im actually more conserned about the sharpness of the lens... actually the total lack of it
>> Anonymous
>>187183
may have something to do with the fact that the camera was skaking or was shook ( shook right?) while taking the picture.
>> Butterfly !xlgRMYva6s
Since you have fairly normal circular bokehs in the centre, it looks more like the lights that are causing the triangles could be to blame.

Got any more pics to demonstrate?
>> Anonymous
>>187191
I think actually, if you actually look at the actual image, you'd actually see that in all actuality, it's actually really sharp.
>> Anonymous
No, the bokeh is one of the things I like about the lens.

But good for you: you've got preferences when it comes to the look of different lenses.
>> Anonymous
>>187197
I think actually that you are wrong. Any lens, i mean any, even those that dont meet the minimum MTF in most tests will produce sharp looking images at that resolution with unsharp mask applied.
>> Anonymous
     File :-(, x)
Right edge again.

Camera-Specific Properties:Equipment MakeCanonCamera ModelCanon EOS DIGITAL REBEL XTCamera SoftwareAdobe Photoshop CS2 MacintoshImage-Specific Properties:Image OrientationTop, Left-HandHorizontal Resolution72 dpiVertical Resolution72 dpiImage Created2008:05:22 18:12:29Exposure Time1/2000 secF-Numberf/1.4Exposure ProgramManualISO Speed Rating100Lens Aperturef/1.4Exposure Bias0 EVMetering ModePartialFlashNo Flash, CompulsoryFocal Length30.00 mmColor Space InformationUncalibratedImage Width1050Image Height700RenderingNormalExposure ModeManualWhite BalanceManualScene Capture TypeStandard
>> Anonymous
That is one hell of a shiny bike
>> Butterfly !xlgRMYva6s
>>187210
They're cool but could be really irritating after a while.

Do you only get them wide open or is a probem through the whole range?
>> Anonymous
>>187210
I kind of like them. Gives it character, and it's not offensive or unattractive.
>> Anonymous
     File :-(, x)
Yes, wide open.

Camera-Specific Properties:Equipment MakeCanonCamera ModelCanon EOS DIGITAL REBEL XTCamera SoftwareAdobe Photoshop CS2 MacintoshImage-Specific Properties:Image OrientationTop, Left-HandHorizontal Resolution72 dpiVertical Resolution72 dpiImage Created2008:05:22 18:21:08Exposure Time1/100 secF-Numberf/1.4Exposure ProgramManualISO Speed Rating400Lens Aperturef/1.4Exposure Bias0 EVMetering ModePartialFlashNo Flash, CompulsoryFocal Length30.00 mmColor Space InformationUncalibratedImage Width1050Image Height700RenderingNormalExposure ModeManualWhite BalanceManualScene Capture TypeStandard
>> Anonymous
>>187210
maybe you got a bad copy of the lens
>> Anonymous
>>187219
I see no triangular bokeh here.
>> Anonymous
It's a known issue of this lens.
http://luminous-landscape.com/forum/index.php?showtopic=21528
>> Anonymous
>>187219
How do you do that extra information in the post after you click on 'here' ??
>> Anonymous
>>187237

that thread is tldr
>> Anonymous
>>187233

It doesn't happen all the time.
>> Butterfly !xlgRMYva6s
>>187233
>>187244
>>187219
Some of the blur is traingle shaped, its not as obvious cause the bokeh is very blury, but its still there.
>> Anonymous
>>187222

sigma can, and i stress can, make some really nice lenses. the main problem with them is that they tend to have really bad quality control or none.

some ppl have a fantastic time and others have a really shitty time having to deal with warranties and such.

its a catch 22 situation.
>> Anonymous
>>187241

Nothing, it's embedded to any image taken by cameras.
>> Anonymous
ive never noticed it in any of my shots taken with this lens in ~1 1/2 years and while it aint stellar from wide(find me a fast lens that is) it does get very good from about f/2 through 11+

highly reccomended :D ;)
>> Anonymous
     File :-(, x)
Serenar, or someone else with equal knowledge about this.

Is there some truth to this?

"And sometihing else. The 35 f/2 is a wide angle lens and has the optical design of one. See the diagrams below and compare the front elements, for example. The 50 f/1.8 is a "normal" angle lens with the corresponding design. The shortcomings of the 35 f/2 are not a coincidence."
>> Anonymous
>>187490
50mms are easier to do well than 35mms. That said, I wouldn't sweat it. Does whatever brand's 50/1.8 you're talking about technically outperform its 35/2? Probably. Does it matter? No, not really. Look at the pictures and decide if you like it. You might like the "inferior" 35 better. Who knows?

Also, 50 and 35 are very different lenses in use; comparing the two is silly.

(Not Serenar here.)
>> Anonymous
I mean, right now, people are using 28-35mm on crop as a normal.

But as you can see, the design is different from the 50mm design.

If someone, maybe the Sigma is like that, makes a 28-35mm using the 50mm design, will it be dramatically different than using these old 28-35mm which are wide lenses as normal lenses.
>> Serenar !m827jEgWi.
>>187490
I actually have no training in optics at all (didn't even do high school physics) so I can't give a real informed opinion.

I guess I'd echo>>187497, but add that it's not that 50mm lenses are easy to make well, but that good lens designs like the Planar (as seen in every modern 50mm lens) makes for good 50mm lenses and above, and is very well researched. The Planar does not really work for wides, and so an inferior design must be used.

The Tessar (4 elements 3 groups) is another design that can produce stellar standard lenses (Leica and Zeiss' slower lenses, the Nikon and Pentax 45mm pancakes). As far as I can infer from lots of reading, you can force this design into any focal length you want, but the design may not be suited for that length (hence why the Leica 50/3.5 Elmar is a vastly superior lens to the 35/3.5 Elmar, even though both are Tessars). However, with newer technology like rare earth glass, you can use old designs for focal lengths they were not suited for, like in the Minox 35 series' excellent 35/2.8 Tessar-type lens.

Or at least that's what I've gleaned from the Internet. Don't quote me on this.
>> Anonymous
>>187499

The Sigma looks like (from the diagram on Sigma's site) a very conventional Planar, except with one extra element added in and three exotic glasses used, two in two different Planar elements and one in the extra element. So yeah, they're doing it. But the Planar isn't an inherently superior design; it's a great design, but it's not the be-all-end-all thing.

Wikipedia "retrofocus" to read on some of the difficulties with most short lenses on SLRs.
>> Anonymous
>>187756
>as seen in every modern 50mm lens

I haven't looked at their diagrams, but I've read Leica fifties (except the Elmar you mention) are an idiosyncratic design, not a copy of any widely used one.

But otherwise, pretty much, yeah.
>> $19.99 !OSYhGye6hY
>>187219
bokeh looks really nice on this lens. The triangle bokeh isn't too bad.
>> Serenar !m827jEgWi.
>>187765
Whoops that should be "in almost every". The Summicron and Summilux names have covered several different designs (Leica lens names refer to speed, not design), including but definitely not limited to the Planar. This is something I'm quite hazy on. Maybe they were modified Heliars or something?
>> Anonymous
is this a sharp lense? is it on par with the nikon 50mm 1.8?
>> des
Looks like total shit, you should post it to me
>> Anonymous
So if someone were to make a 28-35mm using the lens design posted earlier^ with modern coatings and special elements

vs. the "downsized" 50mm design like the Sigma 30mm.

What would be optically better?
>> Anonymous
do it and find out