Mirror lenses (2)

I had a nice walk with the Vectis 400. I took along the Minolta 500 as well but didn't use it this time. No herons, but a lovely red-tailed hawk, and a crow with fall foliage donuts in the background. I haven't figured out how to post images here yet, so no image to share for now.

The LA-VE2 adapter puts some information into the EXIF, but for some odd reason, some of it is inconsistent. The focal length is recorded in a multiple places, as is the f-stop (400mm, 405mm, f8, f8.3). In some programs, the lens is listed as "Sony 400-4mm f8.3" for example. I did some archaeology and found that in the photo processing programs I use, the Sony::LensSpec is given priority over the usual EXIF::LensInfo, and that's where that odd-looking zoom specification with 4mm comes from. It's apparently similar to EXIF::LensInfo, according to the exiftool documentation, but it isn't really specified. Apparently you can set a flag in it to denote a reflex lens, and perhaps you can specify Minolta as the maker instead of Sony. I'll fiddle with it more later and see what I find out, but for right now, I saved a preset in MetaImage, my favorite graphical front-end for exiftool, to overwrite the values as follows. This is only something I do with JPGs, I don't dare mess with raw files since I corrupted some.

Exif Lens Info: 400 400 8 8
Exif F Number: 8
Exif Lens Make: Minolta
Exif Lens Model: Minolta Vectis 400/8 [this is free-text]
Exif Focal Length: 400
Exif Focal Length in 35mm Format: 400
Sony Lens Spec: 00 400 0 8 0 00

anthills wrote: The LA-VE2 adapter puts some information into the EXIF, but for some odd reason, some of it is inconsistent. The focal length is recorded in a multiple places, as is the f-stop (400mm, 405mm, f8, f8.3). In some programs, the lens is listed as "Sony 400-4mm f8.3" for example.

Very strange indeed! The more so as the lens specification of other Vectis lenses is correct.

And: welcome to Dyxum!

darosa wrote: All manual focus, just to be sure. Amazingly sharp!

Better than Minolta Reflex 500mm?

woodrim wrote: mariuszlo wrote: darosa wrote: All manual focus, just to be sure. Amazingly sharp! Better than Minolta Reflex 500mm? Although better needs to be defined, in my opinion, yes. Very close to the 250mm except for the slight vignetting.

+ 1

There’s a reset, which just resets some preferences to defaults, and initialize, which seems to be a thorough wipe. I did the latter.

Meanwhile I’ve done some more shooting. I have multiple copies of the Vectis 400 and I’m having sporadic performance issues with the LA-VE2. It seems better than prior to the reinitialize but still not great. Sometimes it stalls and won’t respond for a while; sometimes it hunts and gives up.

I also have one copy of the Vectis 400 that it won’t operate; the camera screen shows an image briefly as the camera turns on, but then the display washes out to white, and along the bottom, it blinks “F90 ±0.0” as if an F/90 lens is attached. The camera will then not release the shutter in any mode, even M. This copy of the lens has no damage or problems that I can see, e.g. the contacts look fine. I have a Vectis S-1 camera and it operates this copy of the lens without problems. In fact, testing the lens on the Vectis S-1 camera gave me some perspective on AF performance relative to the LA-VE2 adapter: the old camera is actually better at focusing the lens than the LA-VE2 is. It frequently hunts but never fails to respond and always locks onto focus after hunting.

I tried contrast-detect autofocus on my Sony a7r3 with the LA-VE2. That didn’t work at all! Phase-detect is the only thing that is working for me. I have tried Center and Flexible Spot. On some of my other cameras I can shrink the focus zone to a single point dead-center, but I haven’t figured out how to do that on this Sony; is it possible? All I can seem to do is shrink it to a zone that seems to be a grid of about 4x4 or 5x5 focus-detection points.

As far as optical quality of the lenses, I have done some quasi-objective testing under somewhat controlled conditions. I have one copy of the Vectis 400 that is exceptionally sharp and contrasty despite actually having some light dust and even a barely visible fringe of haze around the perimeter of the primary mirror. My other copies that look cleaner and more pristine are very close, optically. One of them was ghastly-bad until I noticed that there was a UV protection filter installed between the front of the lens and the short screw-on hood, which I’d previously failed to notice. Removing that made a huge difference. These lenses are very revealing of anything messing with their optics.

Away from the bench, I have gotten exceptionally sharp and contrasty photos from the Vectis 400 in real-world usage. If you have a good copy, as far as I am concerned it demonstrates that mirror lenses are not inherently limited to subpar performance, even on high-resolution modern sensors. And from what I’ve seen, copy variance is low; I think these were built to a very high standard. I have a lot of mirror lenses and finding good copies of most of them has involved a lottery, but not so with the latter-day Minoltas.

I found an answer to my question about shrinking the focus spot. When I use the Fn menu to select the Focus Area, when scrolled to Flexible Spot, I can use the right/left arrows to choose L, M, or S. The S spot is pretty close to the "single point" I was looking for. It's rainy out right now so I will have to test the Vectis 400 later and see if using a very small focus area helps with the LA-VE2.

Hmmm, I don't recall having that problem but had only done a brief test of the lens after receiving it. I'll give it another try.

I suggest you share with the Monster people all these issues you find. I expect that the adapters will have updates to the firmware like the LA-EA4 conversion did. It may also be possible to learn from them what AF settings they used for their testing. I suspect a great deal of the difficulty is related to those settings.

When I was testing my prototype LA-VE2, I made changes to my AF settings after having trouble. At this time I don't recall exactly what I did and I don't know much about using AF anyway. I also had two friends try the adapter on their A7rIV cameras; one worked well and the other had challenges. It was settings related.