Consider this part two of a discussion from a couple of weeks ago. This time I wanted to highlight a very specific crappy lens; The venerable, ancient Canon 17-40 f/4 L. I would put this lens in somewhat the same category of the Fuji 18mm f/2 in a lot of ways. Wait, what… How the hell are those two lenses comparable? In all obvious ways they're not. Ones an ultra-wide angle zoom that's fifty-two times larger than a tiny APS-C prime. One is f/4 the other f/2, they couldn't be more different right? Sure but in one important way they are similar — they are both whipping boys of the fanboy crowd. Both of them get no sexy-ness airplay and pretty much are only recommended in a backhanded way if you can't possibly afford to buy anything "real".
Above is a quick crappy snapshot I just made while watering a couple of plants I'm trying to start. We'll see if they survive. It's a crappy picture shot without care or consideration but it's a reasonable example to point out a few things.
- First it's cropped 4x5. I deliver a ton of work to clients at 4x5 or 4x3 depending on where it will end up. So again for the 1,000th time who gives a rat's ass about the extreme corners because, wait for it… they never show up.
- Even if it were 3x2 who cares the corners are almost never in focus for most of my subject matter (if they are and are important that things look good I'll use a fantastic prime and or tilt-shift to actually manage focus where it counts. Screw half-measures of relative zoom corner performance.
- This is wide-open at the worst focal length in terms of overall resolution for that lens (but not worst corners maybe).
- Wow, the out of focus areas actually look nice in a lot of ways. I've owned, used, and seen many many zooms both UWA and normal range that are allegedly better but have either god awful rendering or considerably less pretty than above.
So let's see what this useless obsolete from the start lens looks like all zoomed in at 50 megapixels shall we? Sure, why the hell not.
Wow, not that bad. Actually quite good. So good in fact I'd venture to say that the Canon 5DsR + this crappy old lens probably resolves more detail than say a 20-30 megapixel camera with the newest most expensive UWA (maybe not but it would be almost impossible to tell with the 5DsR downsampled to the same size)
All of that aside the 17-40 L is a very useful lens that can be had for a song. It's built like a tank but not heavy. Yes the newest 16-35 2.8 III as well as the 16-35 f/4 L lenses do out perform it in certain circumstances but in 80% of use it really doesn't. I definitely would never buy the 16-35 f/2.8 version I as it in no way out performs this cheap lens except for the 2.8 part (very limited usefulness) and even the version II of the same really doesn't do much better if any. Again it's one of those work-horse lenses that I'll probably never get rid of until it breaks or I have a very specialized need. If I were to need something really wide that was pristine out to the corners I'd definitely go for the 17mm tilt-shift instead why bother with half-measures.
When shooting largish apertures ultra-wide of non-flat things close up (usually where I use this) the corners do not matter in terms of resolution and definitely don't matter at 4x5 aspect ratios.
Images made with the Canon 5DsR and 17-40 f/4 L at 40mm wide open. Processed with defaults SOOC using Capture One 11. Note that if you do shoot non-tethered the 5Ds or 5DsR are a better choice when shooting 4x5 aspect ratios than the 5D mark IV purely due to the viewfinder masking available in the prior models. I was shocked to learn the 5D IV did not have this feature. Screw GPS and wifi, I rarely use those.