You know I've had issues with the DXO lens reviews for a while. I didn't pay attention to them at all until they posted low-ish scores for some lenses I personally knew to be stellar optics. These optics I would always choose to use over alternatives they ranked higher.
Since then my thoughts have been that they cannot properly assign value to the contrast delivered with the resolution. Because that is what I value most, in terms of optics, then their reviews aren't super useful to me. They also ignore physical aspects of lenses pretty thoroughly but that is stated up-front so I don't begrudge them that.
Zoom forward to now, and with their latest Sigma 85mm EX posting they said what I expected them to. They found it to be one of the best lenses they've ever seen. Indeed, I mentioned extremely high sharpness in my own review before basically failing the lens on contrast and usefulness in difficult lighting situations. So we have another DXO review I find of dubious value.
The 90mm Summarit-M is the only reasonable “long” lens for the unreasonable M system, that is both its claim to fame and explains why it doesn’t appear to be very successful in the marketplace. This Summarit also serves as the replacement for the venerable and universally loved 90mm Elmarit-M, a lens that is difficult to replace in the minds and hearts of longtime Leica photographers. As a result the 90mm Summarit-M is a lens that is appreciated in relative silence vis-à-vis the Internet.
When I tested the Leica 90mm Summarit-M (review) I experienced what I consider to be severe focus issues. The lens back-focused at long distances (10 meters or more) and front-focused at short distances (less than 1.5 meters). This caused me to suspect my rangefinder, which I confirmed had grown a small error, but the lack of a true solution after a round of tweaks forced me to research the subject of focus a bit more.
Now I understand the overarching principles just well enough to convince myself that the behavior I observed in the 90mm Summarit-M is by design. It's not because it is desirable behavior, but because correcting it is an expensive affair. This is what ultimately is going to prevent me from recommending the 90mm Summarit-M to all but mirrorless camera users.
A friend of mine asked out of honest curiosity what the difference was between different pieces of high-end equipment. He asked from the point of view of a photography outsider. More precisely, his real question is what does equipement worth $11K do that equipement worth $3.5K doesn't do?
The 24mm Elmarit-M ASPH is an elegant lens emblematic of the M system. It bridges the vast chasm between journalism and architecture, in a form factor that defies all conventional wisdom borne by a DSLR world. How can so small a thing be so sharp, everywhere?
Sorry for the delay getting the latest reviews out. This is what's been going on.
Samples for the 75mm APO Summicron-M ASPH. It's an outstanding lens, though at times it can be difficult to focus and it's not as resilient to veiling flare as I would have wished.