June 25, 2018, 12:44:06 AM

Author Topic: Advice request: 20mm options  (Read 5542 times)

lexaclarke

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Advice request: 20mm options
« on: March 11, 2018, 06:25:49 AM »
Hi there,

I'm looking to add a wide prime to my kit for indoor use. Something around the 20mm range seems right. None of the local stores have any of them in stock to get hands-on with and while I can find example photos from each lens on sites like flickr they're mostly landscape or astro photos and flickr doesn't really tell me much about what the lenses are really like to live with. So I'm hoping someone(s) here can weigh in with some impressions of what any of these lenses are like to use long-term.

Right now I have a 5D mark II with a Tamron 24-70 f/2.8, Sigma 35mm, Canon 50mm STM and 100mm f/2 and a Fuiifilm X100T. I have the 70-200 f/4 IS too but that's never for indoors. The Sigma is my main lens by far, barely use the rest. I'm mostly shooting expos and trade shows, semi-professionally, and sometimes that means trying to get a whole car in frame at short distance or other times it could be a big group of people or an entire company stand. With the 24-70mm f/2.8 I sometimes run out of space indoors. Backing up further sometimes isn't an option at some of the more crowded events. I rented a 16-35 but found I was only really using around 20mm and I don't really like zooms anyway, I'm a prime gal (my 24-70 only gets used for the wide end and I'd like to just sell it), so I figure I may as well get a 20mm prime.

Light is sometimes a problem. I can't often stop down more than f/2.8, maybe f/3.2 on the good days. So if a lens is only good at smaller than f/4 then it's not much use to me. 1/60th f/2.2 ISO3200 is about a normal bright exposure for the shows I'm at.
Autofocus isn't a huge concern because even the notorious Sigma 35mm has been fine for me so far. It's nice to have AF but for a wide angle I'm okay with manual focus.
Coma doesn't matter to me at all. Extreme corner performance doesn't really matter, but I do need more than just center sharpness.
I don't anticipate using filters with this lens.

The biggest deal for me is what it's like to really live with and use the lens day after day. Having to correct for complex distortion or watch for flaring all the time (backlighting and shooting into light a lot at trade shows!) is a big pain for me so I will happily accept a slight drop in optical quality if it means I can avoid those hassles. I do shoot raw but I'm asked to quickly deliver clear, clean files, so I can't really work with a lens which requires a lot of post-processing correction. Whether the weight really becomes a chore is another issue.

So far I'm looking at
  • Canon 20mm f/2.8. It's old and I've read about the strong field curvature, but it's also the smallest and lightest. Reviews suggest it's nowhere near good enough wide open.
  • Sigma 20mm f/1.4. Fastest and seems clear, but it's the heaviest and at the top end of what I'm comfortable spending. DXO and TDP suggest the distortion is pretty extreme too.
  • Zeiss 21mm f/2.8 Distagon. Seems to have the clearest rendering but it's fairly heavy and I'd need to buy the old Distagon version second hand as the new Milvus price is far more than I'm okay spending.
  • Samyang 20mm f/1.8. Hard to find anything about this lens. Not many reviews at all and the few I've found mostly only talk about astrophotography. But my video friends swear by their Samyang Cine lenses.

I've not seen any other options but I'm open to any suggestions.

(Sorry for bumping the apparently dead EF 20mm and Zeiss 21mm threads, but at the time the board wouldn't let me make a new topic!)

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Advice request: 20mm options
« on: March 11, 2018, 06:25:49 AM »

Larsskv

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Re: Advice request: 20mm options
« Reply #1 on: March 11, 2018, 07:03:33 AM »
The Sigma 20mm f1.4 is very good, and I can recommend it. I own it, and it’s main use for me is northern lights photography, but it is good indoors as well.

I also own the Canon 24mm f1.4 LII. I prefer it over the Sigma due to its smaller size and weight, AF, and overall rendering.  You might consider that as well.

lexaclarke

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Re: Advice request: 20mm options
« Reply #2 on: March 11, 2018, 07:08:06 AM »
I was suggested the Canon 24mm f/1.4 in a store, but as the 24-70 already isn't wide enough, I have no faith it'd be any benefit. Plus it's about 1/3rd more expensive than the Sigma or Zeiss.

Larsskv

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Re: Advice request: 20mm options
« Reply #3 on: March 11, 2018, 10:39:15 AM »
If you don’t want the 24mm, and if the size and weight doesn’t bother you, and you don’t need filters, I do recommend the Sigma 20 ART.

Zeidora

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Re: Advice request: 20mm options
« Reply #4 on: March 11, 2018, 11:34:14 AM »
Have the Zeiss 21 and it is one of my favorite lenses. For interior shots, you will appreciate the rectilinear projection. Quality has it's price and weight. Compare the Otus 55 with any other 50-ish mm lens.
5D2 full spectrum, 5DsR, a bunch of Zeiss (some other) primes, for documentary natural history, macro, and micro.

Don Haines

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Re: Advice request: 20mm options
« Reply #5 on: March 11, 2018, 01:51:39 PM »
Got a local camera club? That can be a great source of trying out different gear.....

I’ve got the Sigma 20 F1.4, got it for night skies.... it’s also gotten a fair bit of use shooting “the band” ( not THE “ the band”) in poor light. AF seems good on a 5D2 or a 6D2.

Lightroom can correct a lot of distortion, for any lens with a profile, in a simple click.....
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lexaclarke

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Re: Advice request: 20mm options
« Reply #6 on: March 11, 2018, 05:32:44 PM »
No, nothing local, not even a rental service. I had to travel two cities over to rent the 16-35.

Seems like the Sigma and the Zeiss are the most commonly used options. Like the Canon has been long forgotten and the Samyang hasn't been picked up by anybody. The Sigma does seem to make the most sense on paper but that Zeiss is so tempting. 'Cause it's, well, a Zeiss, you know?

you will appreciate the rectilinear projection.
That means upright straight lines will stay straight, right? Or is it that the plane of focus stays straight? I knew this once but I forget, it's not something you have to think about very often! ;D

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Re: Advice request: 20mm options
« Reply #6 on: March 11, 2018, 05:32:44 PM »

Zeidora

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Re: Advice request: 20mm options
« Reply #7 on: March 11, 2018, 10:24:47 PM »
you will appreciate the rectilinear projection.
That means upright straight lines will stay straight, right? Or is it that the plane of focus stays straight? I knew this once but I forget, it's not something you have to think about very often! ;D

rectilinear = straight lines are straight, very little pincushion or barrel distortion. It is not a TS lens, so if you tilt it (sensor not parallel to wall), you still get falling lines due to perspective. Re focus breathing, I never worry about it with any of my Zeiss lenses. One of the reasons I use them over anything else. If you want to go wider, the Zeiss 15 is also astoundingly well corrected.
5D2 full spectrum, 5DsR, a bunch of Zeiss (some other) primes, for documentary natural history, macro, and micro.

Refurb7

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Re: Advice request: 20mm options
« Reply #8 on: March 11, 2018, 10:42:28 PM »
Canon really ought to update their 20m f/2.8.  It's about time!

NorbR

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Re: Advice request: 20mm options
« Reply #9 on: March 12, 2018, 09:50:32 PM »
I also own and love the Zeiss 21mm Distagon, and I could sing its praises ... you'd certainly not be disappointed with that lens.

One thing to keep in mind is the vignetting, it's quite pronounced wide open, and since from what you've said it sounds like you'd be living at f/2.8, it's something you'd have to deal with a lot. Up to you to see if that's a problem. I don't know much about the Sigma but I'd imagine that with that large front element it would suffer much less from vignetting when stopped down to f/2.8.

The Zeiss is also not immune to flaring, though it retains contrast very well, which is one of the reasons why I like it so much for landscapes. Not sure what that would mean for interior work, that's not how I personally use it. Also no idea what the Sigma is like on that front.

That being said, given your typical lighting conditions, I struggle to find reasons why you would NOT go with the Sigma. Being able to grab those two extra stops of light when you need them seems like a huge advantage, and from everything I've read about that lens you wouldn't be giving up much, if anything, in terms of IQ.
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Mt Spokane Photography

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Re: Advice request: 20mm options
« Reply #10 on: March 12, 2018, 10:11:17 PM »
I have a 17mm prime lens from Tokina, and find its very good.  Its f/3.5 and auto focuses nicely.  Tokina discontinued it, so they are only found used, but the price can be reasonable, I paid $125.  I see a Zeiss 21mm ZE f/2.8 locally for $695 that sounds like a deal, but 17mm is a lot wider.

Don Haines

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Re: Advice request: 20mm options
« Reply #11 on: March 12, 2018, 11:16:07 PM »
Here is an indoors example with the Sigma 20 F1.4, shot at F1.4

AF is set to spot and using the centre point, and centered on the coloured sash in the middle of the frame.

I chose this wall as the vertical lines make it easier to notice distortion. The walkway on the top is not straight, so the wobble on it is not distortion.

The first shot is the image straight out of the lens and resized for the forum. The second image is with the Sigma 20mm lens profile selected in lightroom. No other editing was done. Note the change in the amount of vignetting between the two images.

The cat is in the picture because the internet can always use more cat pictures......
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Zeidora

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Re: Advice request: 20mm options
« Reply #12 on: March 12, 2018, 11:21:22 PM »
One thing to keep in mind is the vignetting, it's quite pronounced wide open, and since from what you've said it sounds like you'd be living at f/2.8, it's something you'd have to deal with a lot. Up to you to see if that's a problem. I don't know much about the Sigma but I'd imagine that with that large front element it would suffer much less from vignetting when stopped down to f/2.8.

Light fall-off towards corners (aka "vignetting") is simple 4th order function of f-stop and covering angle (at same sensor size that is equivalent to focal length), so independent of manufacturer. Ray's book on photographic optics explains it in more detail. The only way you can get rid of it before taking the image is with a center filter, which is a graduated ND filter that is darkest in the center, and becomes lighter toward the periphery. Don't think it exists for any of the discussed lenses. They are usually matched for particular lenses, and have an ideal f-stop, usually at 8 or 11. Have a couple for my Schneider 72 and 90 XL for large format. Cost on there order of $4-600 each, some have been discontinued.
These days, easier to fix digitally with a layer mask.
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Re: Advice request: 20mm options
« Reply #12 on: March 12, 2018, 11:21:22 PM »

lexaclarke

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Re: Advice request: 20mm options
« Reply #13 on: March 13, 2018, 04:27:58 PM »
Thanks for the photos, Don, they're much more the kind of thing I need to see. It certainly doesn't look like the Sigma's distortion is too destructive to correct and the vignetting looks manageable.

Seems like the Sigma is the smart choice. Maybe I'll have to satisfy my Zeiss lust with a 50mm or 100mm upgrade instead, once I've picked those winning lottery numbers.

I must say I'm surprised that seemingly nobody has used the Canon lens. Usually I get shouted at for even daring to consider a third party lens. I know the Canon 20mm is old and doesn't seem that great but even the worst Canon lenses usually have a few fans ;D

Frodo

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Re: Advice request: 20mm options
« Reply #14 on: March 13, 2018, 05:10:05 PM »
Hi lexaclarke, I had the EF 20/2.8 and even in the days of the original 5D it was very underwhelming.  I replaced it with the EF 20-35/3.5-4.5 zoom and it was much better at 20mm.  I now regret selling that lens - it was nice and compact, but very slow at 35mm.  I then bought a Voigtlander 20/3.5 manual focus lens.  It was okay in the centre but soft on the outside.  It had terrible coma and needed to be stopped down to 5.6 to be usable for astro photos.  It was a nice companion to my 35mm when hiking, but didn't get much use, so I sold it.
My ultra-wide needs are covered by the Samyang 14/2.8.  This is fully manual, but this is usually not a problem, and is sharp and has little coma - a great astro lens.
If gear matters: 5DsR, 6D, M3, Samyang 14/2.8, EF 24-105/4, EF 35/2.0IS, EF 50/2.5 macro, EF 85/1.8, EF 200/2.8II, EF 400/5.6, EF-M 11-22/4-5.6, EF-M 18-55/3.5-5.6, EF-M 55-200/4.5-6.3, Ext 1.4x, Lifesize conv, Ext tube EF25, 270EX, Godox XPro-C, TT685-C and TT600

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Re: Advice request: 20mm options
« Reply #14 on: March 13, 2018, 05:10:05 PM »