Toothwalker wrote:
If you want to compare foreground details, you should focus on the foreground. Not on the
background.
+1
Different lenses have different field curvature characteristics as well
On a side note, I find it very curious that most Zeiss lens designs have really odd curvature of field characteristics, something they didn't bother to correct even in their more recent designs for Sony or ZE/ZF series. There must be a reason for this, and I would venture to say this must be connected to the special Zeiss look, perhaps the 3D effect, that is so particular to Zeiss. Just one of my unproven theories
Field curvature varies with the optical formula. The Planars have a very flat field of focus (hence the name; Planar) whereas Sonnars and Distagons are different in that aspect, at least to my eyes. With a neutral/even background I just love the Planars, the Sonnars never really got me where I wanted. I prefer the "look" and "pop" of the Planars but they can produce harsher bokeh (in my opinion) whereas the Sonnars lack the snap of the Planars but most often produce a nice bokeh. Distagons, well, haven't made up my mind on them but I do prefer the Biogons (of the G-series) to the SLR Distagons when it comes to wideangles.
edwardkaraa wrote:
IMHO, infinity adjustment is a recipy for disaster as you're fooling with the entire lens formula, with all due respect to Pham Minh Son. In my experience, you need exactly 1.49-1.50 mm to get infinity focus on an untampered with lens. The only adapter on the market that does this afaik is the Kindai/Cameraquest, plus an unknown brand called Phepan that I discovered by coincidence. I got infinity focus exactly at the infinity point on all my 13 Zeiss lenses (that I've just sold) with the mentioned adapters. I have 13 fotodiox consumer adapters sitting in my closet as they are useless. They made the lenses reach infinity several millimeters before the infinity mark. This messes with the lens optical formula and increases CA etc, unlike slightly thick adapters that act like extension tubes. Haoda adapters are no different, just with an added chip. This is my personal experience, ymmv.
I shimmed the Haoda Fu adapter with metallic duct tape in four spots around the flange to keep it parellel with the flange mount. It now measures 1.49mm.
It's unquestionably sharper at f16 in the corners than it was with the unshimmed Haoda Fu adapter. Unfortunately, I left my tripod in the country yesterday, so I can't do a tightly controlled comparison test with the Zuiko - but I'll say this: you are 100% correct about desirable flange thickness, at least as far as I can tell from a handful of handhelds..
You know, a lot of times it's better to just plain be wrong about something and learn a lesson than it is to be right. Many thx, Edward, and to Paul for confirmation.
The only problem I see now is that I might have to keep BOTH the Zeiss and the Oly...
Thanks for the comparative test, David. I picked up an Oly 18 about a week or so ago, but still waiting on delivery...must still be tied up in US customs (I hope this isn't the "change" that we were promised ). Hopefully it'll be here soon and I can start shooting with it. Its nice to see how this little guy does...
One nice quality of the the Zuiko 18/3.5 is that it has almost no distortion. Of course, it is also the smallest superwide ever made for a (D)SLR. It's a lens that can always be packed along.
how did you shimmed the adapter? Was the lens a little bit loose prior to shimm?
In other words, how did you know on which spots to shimm?
I used aluminum duct tape. I just held it on the edge of the adapter and pressed with my finger to trace the outside of the flange, then cut them out with a scissors. I made four pieces and mounted them at 90-degree spots to keep the flange parellel with the flange mount. I put the tape on the camera side of the flange. My adapter was not loose before, and surprisingly enough, it doesn't feel any tighter now.
The aluminum tape is very thin, but it won't tear and so I don't have to worry about spreading a sticky layer of adhesive around. If I decide to keep the Zeiss, I'll probably follow Edward's advice all the way and put a CameraQuest adapter on it.
kosmoskatten wrote:
Field curvature varies with the optical formula. The Planars have a very flat field of focus (hence the name; Planar) whereas Sonnars and Distagons are different in that aspect, at least to my eyes. With a neutral/even background I just love the Planars, the Sonnars never really got me where I wanted. I prefer the "look" and "pop" of the Planars but they can produce harsher bokeh (in my opinion) whereas the Sonnars lack the snap of the Planars but most often produce a nice bokeh. Distagons, well, haven't made up my mind on them but I do prefer the Biogons (of the G-series) to the SLR Distagons when it comes to wideangles. ...Show more →
Henrik, despite the Planar name, Planars have a wavy field curvature . Almost all Zeiss lenses have this in some way or another. (They were called Planars in the 19th century, that time cars doing 10 kph were considered fast )
OK, David, et. al. here are samples from the Tamron 17/3.5. Straight from Bibble Pro, capture sharpening applied only. No colour or tone curve work. Some sensor dust fixed and then straight out to JPEG with no USM on the JPEGs.
Paul, try focusing a bit further away, like from 5m or more. I bet you'll see corner performance drop a bit. My 17-40 is like that. Corner performance degrades the further away the plane of focus becomes.
Nice lens, though. I've never seen one on the market. What's a decent price?
has anyone tested a newer zeiss 18mm vs older ae ?
I don't know about the 18mm but i know that several lenses including the 25mm were improved quite a bit in later years. (I had an old 25 ae which had awful edges but a newer one was sharp - a few years later a fellow claimed that they did a scientific study of the 25 while at school and found a date when it changed and had zeiss confirm the change).
Anyways the 18mm has a poor reputation on the various mailing lists I've read but I'm curious if anyone has actually checked if there was an optical change over the years.
pdmphoto wrote:
The Zeiss 18mm was found to have similar corner (un)sharpness in a test done by Mike Hatam a few years back here on FM. He tried several adapters. His test is what convinced me to buy the Oly 18/3.5. The Zeiss corner performance also shows in Zeiss' own MTF's for the lens. It is a very old design.
mawz wrote:
KEH has one with the (rare) hood/filter adaptor for $265 in EX and one with no hood in BGN for around $170. I payed around $150 for my copy.
My second copy came with the original hood, caps, box, instructions, etc. but it is a BGN condition copy. I suspect that it is mildly de-centred. I will likely get it tuned up at some point.
). Hopefully it'll be here soon and I can start shooting with it. Its nice to see how this little guy does...