David Kinston: I'm crying - you ignored my sigma 85/1.4 boohoo
David, unfortunately we didn't have enough copies in-house to do the Sig.
Horshack: The copy variation scores in Roger's tests for some of the more expensive lens is appalling and unfortunately matches my own experience. Over the course of two years I've tried 3 different copies of the Canon 24-70 f/2.8 II and have yet to find a copy that is anywhere close to reasonably centered, even stopped down to f/8 and tested on a lowly 5D. Here are photos of two samples, as compared to my 24-105 which is perfectly centered
Copy #1, 24-70 f/2.8 II @ 50mm f/8 vs 24-105 on 5D:https://horshack.smugmug.com/photos/i-6NghqG2/0/O/i-6NghqG2.jpg
Copy #2 - 24-70 f/2.8 II @ 35mm f/4 on 5D (right side tilted/soft):http://horshack.smugmug.com/photos/i-S8ncn7M/0/O/i-S8ncn7M.jpg
24-105 @ 35mm f/4 on 5D:http://horshack.smugmug.com/photos/i-2rN4XcB/0/O/i-2rN4XcB.jpg
We're doing 70-200 f/2.8 zooms now and should have results pretty soon. I'm not sure we'll get to the f/4s anytime soon though. You make a great point about IS units adding variability, paritcularly with regards to the Canon 70-200 f/4 IS. I've been told that the first two generations of IS did, indeed, add a lot of variability, but that newer IS units have much less effect. But that's been exactly my impression with lenses like the Canon 70-200 f/4 IS, 100-400 IS, and 300 f/4 IS. Rgoer
win39: I wonder whether Lens Rentals has ever tested a single lens 10 times and gotten variation?
It is a really good point, and of course we have. That's one of the things that got us moving from Imatest to an optical bench. Bench variation is less than 1% compared to 3 to 4% for repeated measurements with Imatest.
Ednaz: I've seen this on almost every Nikon owned, not at f16, but when shooting macro and working at effective apertures of f32 or higher. Not as dense as what's shown, but visible in that specific situation - macro, highly stopped down.
I suspect that there's a "tolerance" level for the spots...
We reported it to the manufacturer 3 days before publishing, making sure they weren't sandbagged by it. But we are not a retailer of the manufacturer. We buy our stuff from camera stores just like everybody else. Roger Cicala
Peiasdf: Isn't Roger "Len's Rentals" so why is he saying management tell him this and that?
Always enjoy reading his lens test and disassembly.
I had a great time starting Lensrentals, but I haven't been Lensrentals in a long while. There are 70+ people working there now. My skills don't include managing a big company.
Several years ago I sold a significant portion of the company to the guys who were actually running it: juggling depreciation, following human resources guidelines, negotiating logistics, and all that business stuff that I don't really know how to do, and never want to learn.
I still run the quality assurance and repair departments, but don't do anything with day-to-day operations - management runs that and I stay out of their way except at monthly meetings.
sneakyracer: Lens Rentals stopped shipping to Puerto Rico for the same reason even though Puerto Rico is part of the US Postal system. I needed some gear while I was there and Lens Rentals said no way. Never again. Too bad, I liked their service.
We discontinued Puerto Rico not so much from theft, but simply because there were so many delayed shipments (and we refund the rental fee if things arrive late) that we were eating 1 of every 3 rentals to PR.
Adam Maas: So Lens Rentals Canada has chosen to halt all shipments with Canada Post and instead ship via Canada Post??? Really?
Hint for non-Canadians: Purolator is Canada Post's courier service.
And yes, Purolator does use a lot of Canada Post infrastructure, including most Post Offices. They do use some different distribution centers in major cities but for most of Canada the only difference between the two is the paint job on the van.
Actually, I think they're doing a very right thing and fulfilling the orders they've already committed to, and using Purolator as the lesser of two evils for doing so. But they aren't accepting new orders at all.
JATO: Scotomaphobia Eliminator
PS, whats with the big hammer, is that the fine adjustment tool?
We just use it as a threat - we tell the lenses we can do this the easy way or the hard way. Actually we had to tap in one of the desktops that had gotten a bit bent in shipping.
Debankur Mukherjee: Is Mr Cicala trying to prove that the D600 had no sensor dirt issue ?
Antony, that's exactly it. And over time the D600s have less dust than they used to, so it became less of a problem.
KariIceland: The problem with Lens rentals also is they send you the lenses with a CRAPPY UV filter on the front.
I can't speak for other houses, but Lensrentals does not send UV filters on lenses.
Plastek: Good test. Guys at LensTip.com made similar tests (only never published the results) and came to a similar conclusions - adapters are completely random and getting an acceptable one - perfectly centred with accurate flange distance - is impossible. That's why they test lenses on native bodies instead of comparing all of them in a single body and single sensor (what would allow cross-system comparisons).
So much for all these people thinking that shooting mirrorless with adapters is a valid way for photography.
I just want to throw my $0.02 in: I agree with everything in this series of comments. Like Iskender said, pixel-peeping gets frustrating and expensive, and like Andy said, it usually doesn't matter.
The point behind a lot of what I do is basically trying to say there are no absolutes in photography. When people say 'adapters don't have any adverse effect at all', they're wrong. When people say 'adapters always screw up the image', they're wrong, too.
The coolest thing about photography, to me, is balancing all the compromises so we get the best images. I guess I see my bit as pointing out where some of the compromises are so we can make educated decisions.
Every so often, I read an article and think, "man, I wish I'd thought of writing something like that." This is one of those. I enjoyed it immensely.
My first digital camera was actually an Apple QuickTake 100, which shows you how old I am.
photo nuts: The title and extract taken from Cicala's long article are SO MISLEADING. One should really go through the original article.
As Richard said we discussed this (and I will add I found the discussion useful - Richard and Shawn had good thoughts about why this might be occurring).
I thought the 70-200 f/2.8 data was the most interesting of the repair frequency data tand was appropriate to look at as a subset. A lot of us own those lenses. I've always tended to think because they're so well built they're bomb-proof, which turns out not to be the case.
doctorbza: I'm sure Roger is thrilled that his work has been filed under "Epic Fail".
It wasn't on the list (5% most repaired). We've only had the 70-200 f/2.8 VC in stock for 6 months or so, though, so it's early to say much other than looking good so far. Roger
Thank you, doctorbza! That just made my day :-)I'm sure a lot of people file most of my work under "Epic Fail". Roger
Philly: Amazing that he doesn't wear any gloves while doing this. Isn't there a risk of getting oil from the finger tips onto the components? It doesn't seem like a very good practice.
Some do wear gloves but I hate the loss of tactile feel that causes. I'd rather clean things if necessary during reassembly than strip a screw or tear a flex that was glued down during the disassembly of a lens for the first time. It's amazing to me how much fine sensation is lost by even a thin pair of gloves doing work like this. After we've been in a given lens a time or two and know what to look out for, it's less critical, but the first time I want everything on my side.
I keep my hands off any electrical contacts, touching those only with tools - rubber shod forceps - but generally avoid touching them at all. Same with glass elements.
If I do put on gloves its during reassembly which also includes a lot of cleaning with contact cleaner, alcohol, etc.
Samuel Dilworth: How can a lens have on-axis astigmatism? Clearly something’s wrong there: either the lens is improperly manufactured or the test is faulty, or both.
More generally, I’m not sure this is a particularly useful test:• it tests three good lenses, on-axis, near the middle of their zoom ranges, i.e. it minimises optical differences. Naturally this brings sensor differences to the fore. In the real world, the more important differences are off-axis, often with poorer lenses or good lenses at weaker settings• it compares a camera with an anti-aliasing filter to one without (or with a nullified filter), but no mention is made of the image processing techniques used, leading me to suspect no sharpening was applied. You might think no sharpening would level the playing field, but in this case it would prevent a useful comparison• it compares resolution at an MTF of 0.5, which is a poor substitute for comparing two images visually
It is what it is, but it’s not very practicable.
Thank you Samuel. It's something I'm trying to figure out as we learn this new equipment. Those are helpful points.
This is a very pertinent point and one I can't say I understand completely. The graphs printed are for single lenses, but the results consistent with each of three copies.
The bench lens mounts were an obvious question, but the Tamron lenses were the same on both Canon and Nikon mounts, so I don't think the mount is an issue.
I don't know the answer, but here's one bit of data we've seen on numerous zooms: many show slight on-axis astigmatism at one area of the zoom range but not at others. I don't think element tilt would cause an on-axis asitmatism (it certainly makes off-axis go crazy) but I believe an element spacing issue could. My thoughts, since this seems more common in zooms, is element spacing can't be perfect throughout the zoom range - at least not given current manufacturing tolerance.
But that's just my current thought. Perhaps some of the people with more optical physics than I can confirm or correct that.
h2k: The news item's wording seems to indicate some kind of promotional intent in favour of the lens rental service. The news itself could have been explained with a less promotional flavour. Yet the story was surely worth to be on DPR - also as a good change to the usual - and it caused some entertaining commentary.
If there were no pictures we'd send him replacement gear. As long as there isn't water in the lens, it's covered. Pictures of the event are a fun bonus, but have nothing to do with replacing the equipment or covering the damage.
taotoo: If LensRentals is financially connected to this site have we been told?
Lensrentals has no financial connections or arrangements with DPR.