I have a Canon 24-70 2.8 L and is now looking to a ultra wide angle lens and found a old 20-35 2.8 L lens for far cheaper than a 17-40 or 16-35.
My question is if the 20mm is wide enough from 24 to see a real difference in what you get in the shot or is it better to save up for a 16-35 or 17-40?
I would mainly use the lens for landscape and indoors shots thanks to the 2.8 aperture. Could it also be good for astro photography?
The 20-35L was alright, and the difference between 20 and 24 is significant. But the difference between 17 and 20 is equally (or slightly more) significant, because each millimeter of focal length gets more and more significant as the focal length shortens.
If you want to save money, get an old Canon 20-35 USM (non-L). It was acceptably sharp - probably equal to the 20-35L -- but isn't as contrasty as newer designs. (Contrast is easily boosted in post.)
The 17-40L is a great lens everywhere except in the very far corners at 17mm, and is not very expensive for the quality of output you get.
But the best of all (under $1000) is the 16-35/4L IS, which is fantastic all across the frame from corner to corner.
I still have the 20-35mm f2.8L which I bought pre-owned in August 2002. It was good in its time - and of course is an "L" anyway - but there are better choices now. I got it repaired by Fixation UK a couple of years ago as I'd dropped it, can't remember bu I think it was the front element. It was very cheap to repair - perhaps Fixation just happened to have some spare parts they'd never thought they'd use.
Anyway, as regards the performance I am aware that the composition edges are a little soft compared to current L lenses. Fixation confirmed that is the nature of the lens of that era. Probably no-one would have noticed in the days before digital and pixel-peeping.
As regards 20mm v. 24mm yes that is significantly wider. I still use the lens for video particularly for wide establishing clips and on a B-cam.
I now use the Tamron 15-30mm f2.8 G2 for wide-angle photography. That is very well regarded e.g. look at Dustin Abbott's reviews on Youtube and it is a steal price-wise especially if you buy grey from the Far-East. It is weather proof and has around 5 stops of stabilisation available. The only downsides are it is heavy and it does not take filters on the front. But the only filter you'd consider using these days anyway might be a circular polariser and that does not work well on wide lenses anyway because of vignetting.
You may want to consider upgrading to affordable full-frame—the FOV of your 24-70 on FF is wider than 20mm on 1.3x crop, and the 6D is around $450 USD on the used market. A better camera in every way for landscapes and astro.
I’ve considered the 20-35, as a well-built and small lens for its range. The 17-35/16-35mm f/2.8 (i and ii) lenses are better FL ranges and probably have a bit better image quality. I have the much improved 16-35mm f/4 IS. I really enjoy it, and it sells for around $700 USD regularly.
I’ve heard good things about the Tamron Ashton mentioned.
20 is noticeably wider than 24, and 16 is obviously wider than 20.
If you’re shooting astro... I’ve heard good things about the Rokinon 14mm f/2.8 manual focus primes and Sigma’s 14mm and 20mm ART lenses, too.
If you’re still using the 1D2N and 7D in your profile...
Almost any lens will look good, sharpness-wise, on the 1D sensor. I liked my 1D2 before the shutter failed. On the 7D, you’ll have better results with APS-C or otherwise modern lenses that perform well at high pixel density.
If you don’t need astro speed and coma correction (and don’t want to go to full frame right now), the EF-S 10-18mm covers ultra-wide on the M3 and 7D as well as 16mm does on FF.
I borrowed a friends 20-35 2.8 L for an Alaskan aurora trip. I liked the lens. It showed significant coma at the edges but the aurora images were still very nice. The f2.8 was helpful for the long exposure times vs my 16-35 f4. Regarding the question of is it wide enough, this is personal I think. I find lenses wider than 24 more difficult to frame well. If wider seems appropriate to me then 20 usually achieves it. I have a Voightlander 20 mm pancake prime that I usually use instead of my 16-35 f4 as supplement to my 24-105. Having 20mm available is really handy at times, but again, this is personal preference. I'll add though that an L lens is always better than the non-L no matter what the vintage, IMHO.
Edit: Oh yah, my comments are regarding using on full frame.
drimer's and Jeff's replies clued me in to the fact that you're not shooting on full frame. That affects my advice in two ways:
1. The differences in focal length (20 vs 24, and 17 vs 20) are not so dramatic on APS-C or APS-H as they are in full frame. So I encourage you to look into something wider than 20 if you really want to get into wide angle. The 17-40L is a better choice than any zoom starting at 20 mm.
2. I warned in my previous reply that the 17-40L is weak in the far corners at 17 mm. That doesn't apply in your case, because none of the camera bodies you use actually capture that part of the image circle. So that makes the 17-40L even more viable as a choice for you. Look for a used one in excellent condition.
Edit: Here are some images illustrating the differences between full frame, APS-H (1.25X) and APS-C (1.6X), with wide-angle compositions. (I think these were shot at 16 mm.)
From your description, I think 20mm may not be wide enough, especially if you are using a crop-sensor body.
For most walk-around and landscape situations, I'm quite happy with usefulness of the wide end of my EF 24-70 lens [full-frame]. I also bought a WA lens for travel photography.
I have the EF 17-40 f/4 [for use on full-frame cameras]. It satisfied my expectations to use for architecture and interiors in Europe. I'd made a cost-based decision between the 17-40 f/4 and perhaps the preferable 16-35 f/2.8. And I've never regretted that decision. However, even 17 mm on full-frame may be too limiting for your described use.
I've used it outside as well. My last two use cases explored the limits of both 17mm and f/4. The lens barely let me take the picture I wanted.
For landscapes, this admittedly extreme WA composition barely fit in 17mm...Palouse Falls Palouse Falls by Stephen Shoff, on Flickr
For my type of astrophotography, the Milky Way, both 17mm and f/4 were limiting. The Milky Way barely fit, and f/4 is too slow to stay within the 20-30 second exposure limit to avoid stars streaking.
I think a 16-35 makes more sense here. The f/4 IS is the lens I'm using (on APS-C and APS-H cameras) so that's my default recommendation. However if f/2.8 aperture is needed, it's becoming more complicated.
In the days of yore (okay... that was only 10 years ago) I was using a Canon 17-35/2.8 L lens. It's a more modern design, pretty similar to yesterday's L lenses actually, as it has USM but no weather sealing (actually it's of the same vintage as the 135/2 L). The downsides compared to its descendants are the longer MFD (42 cm vs 28 cm) and - per the testing results I've seen elsewhere - very soft corners at 17mm, even on APS-C. I would definitely choose this lens over any of the AFD ones.
Now the choices for fast UWA zooms are broader... There are the Tamron 15-30 and the newest Sigma 14-24.
If primes are to be considered, I think looking at the Samyang AF 14/2.8 makes sense. It's a relatively new design. Besides, there are three other 14/2.8 offbrand AF primes in existence: from Sigma (oldest but equipped with HSM), Tamron (very rare, never seen one) and Yongnuo (the newest and the unknown of the bunch, and interestingly enough, the scheme isn't like any the Canon 14/2.8 so it's not a copy). I have the Sigma and it's an interesting lens but I'm not sure I'd exactly recommend it to anyone; it's acquired taste.
Finally, for APS-C and APS-H, considering dedicated APS-C UWA zooms is a sensible strategy, methinks, but that's a subject for a whole different post...
You cannot beat the 17-40 f/4 and 16-35 f/4 for the money. The 17-40 can be had for <$350 used these days and you might even be able to find a 16-35 around $700.
If f/2.8 is a must then probably the Tamron 15-30 VC is the one. The optics are great but it's a bulbed front element and evidently huge.
If you need filters, f/2.8, and good optics then 16-35 f/2.8 II is probably the best bet. The edges are weak for the price point however. If you need filters, f/2.8, and excellent optics then the 16-35 III is the only game in town.
Since you are shooting cropped sensor, you might be interested to check out the terrific Canon 15-85/3.5-5.6 IS which has nearly "L" quality and never disappoints. I finally bought a used 20D to support it, years after selling my 60D in favor of FF shooting.
Since getting the 20D, I've also repurchased the equally terrific EF-S 10-22/3.5-4.5 lens. Both these lenses can be mounted on Sony FF mirrorless via adapters with full electronics and slightly wider 1.5X magnification, compared to Canon's 1.6X. The lens provides angle of view equivalent to 24-135mm on FF.
The amazing 15-85 IS can be purchased now for about $300 on the used market.
Thank you a thousand everyone for such informative responses! I have seen I've made a big misstake and not updating my profile and not writing in this thread that I use FF now. I have a 6D and a old 1ds mark II.
To anyone that has the time to update their answers knowing want it for FF is very much appreciated! My biggest question is still if 20mm will be a significantly wider than 24mm of my 24-70?
I will check out all other lenses mentioned in this thread to as there are some I didn't know of before. Price is also of importance, the budget isn't to big.
I had assumed you are using FF, possibly I'd picked up on that from one of your other recent thread posts. My opinion stands that there is a significant difference between 20mm and 24mm.
