Originally posted by reh321 Do you have personal experience with this particular lens?
Well there are four main versions, two by tokina (8 element and 5 element) one by komine, and an earlier preset t-mount version see
review page (to which I contributed most of the tech details). I had a 8 element tokina, which was a poor performer and I sold it, and I have a 5 element one which I am also unimpressed with. I haven't had a komine version but online reviews don't rate it - there is a detailed one on mflenses which is rather critical. However my comment was something of a generalisation based on checking out numerous 400mm's, mostly f6.3's (which actually tend to be better than the 5.6's IMO, the gain in specification I think came with a concomitant slight loss of IQ), all of which have proved to be at best only just about maintaining the level of IQ with a TC, at worst showing pronounced decline. And that is in ideal conditions: as soon as the light drops from bright sunshine the technical aspects of that 2 stop loss of light - low shutter speed (or high ISO) with inevitable shake/vibration, focus difficulty - are such that I stand by my
"waste of time" comment. As a useful rule of thumb, if the TC doesn't give you a bit more in the image over simply resizing an image without the TC by 200%, then you have to question its use.
I shall mention further that most of my testing was done with my mirrorless cameras, at least with mirrorless you get
1. auto brightness compensation in the evf
2. magnified focus assist (5x to 8x) giving superior focus accuracy over anything my K5 (and I would suggest any optical VF dslr) can do , whether in LV or with my VF magnifier.
And a second rule of thumb: TC's work best with the best lenses. With consumer level lenses like these viv 400's, TC's magnify and multiply the optical flaws more than the image.
As a useful illustration of IQ degradation, yet also measurably increasing the information in the image,
cooltouch on mflenses did this test with a quality 300mm f2.8 and stacked tc's:
http://forum.mflenses.com/fun-with-teleconverters-t72307,highlight,%2Bteleconverters.html
And finally to answer your second question: I am enjoying my recently acquired FD 400mm 4.5 on my mirrorless cameras, with my FD adapters - not a specification of lens for which a modern/AF equivalent could be obtained for the ~$250 odd I paid. And I am trying out a couple of tc's with it. You can see some pics with this lens in the
300mm lens club. Though I have to say that even with an OEM lens of good quality, my tests with Tc's so far struggle to pass the resizing benchmark I suggested above.
Last edited by marcusBMG; 11-09-2016 at 08:51 AM.