psss Posted October 27, 2015 Share #1 Posted October 27, 2015 Advertisement (gone after registration) does anyone know if the 24-90 is parfocal? Link to post Share on other sites More sharing options...
Advertisement Posted October 27, 2015 Posted October 27, 2015 Hi psss, Take a look here SL 24-90 parfocal?. I'm sure you'll find what you were looking for!
eckart Posted October 27, 2015 Share #2 Posted October 27, 2015 What does parfocal mean? I might be wrong, but as I understood the technical description from Leica there is just one lens moving for focusing. That's the reason for the remarkable speed. Link to post Share on other sites More sharing options...
psss Posted October 27, 2015 Author Share #3 Posted October 27, 2015 parfocal means that focus remains constant throughout the zoom range.....for example: at 90mm you can focus on an object and that object will remain in focus when you zoom out all the way to 24... Link to post Share on other sites More sharing options...
IkarusJohn Posted October 27, 2015 Share #4 Posted October 27, 2015 parfocal means that focus remains constant throughout the zoom range.....for example: at 90mm you can focus on an object and that object will remain in focus when you zoom out all the way to 24... Good question. My experience of zooms is that this is rarely achieved. Just for clarification, with AF for this to be relevant you would need to, say, zoom right in to get the focus you want, lock the focus (pressing the joystick, if I understood that correctly) and then zoom out to reframe at the set focus? Link to post Share on other sites More sharing options...
psss Posted October 27, 2015 Author Share #5 Posted October 27, 2015 this is mostly relevant for motion application....cine zooms are parfocal....focus remains while you zoom in....for stills it is not really important and almost no still zooms are.... Link to post Share on other sites More sharing options...
pico Posted October 27, 2015 Share #6 Posted October 27, 2015 A perfectly parfocal zoom lens means you should be able to focus at maximum focal length, then draw back to retain focus. Let us just agree that Leica lenses are certainly parfocal enough compared to much earlier technology lenses that probably are older than you are. Bottom line, do not worry about the term and make pictures. Link to post Share on other sites More sharing options...
digitalfx Posted October 28, 2015 Share #7 Posted October 28, 2015 Advertisement (gone after registration) It is critical for shooting video, and since the SL is marketed to this audience it is a relevant question. Link to post Share on other sites More sharing options...
psss Posted October 28, 2015 Author Share #8 Posted October 28, 2015 considering that cine zooms are usually in the higher price range (20-50000) and still lenses usually are not parfocal because there really is no need for it, i would say this (and the other Sl zoom) aren't, i was just wondering if anyone had any input... sony just came out with a 28-135 f4 cine power zoom that actually is parfocal.....and it is only 2500$....so maybe leica worked some magic here as well... Link to post Share on other sites More sharing options...
Jeff S Posted October 28, 2015 Share #9 Posted October 28, 2015 A google search pulled up a Lloyd Chambers blog post on the SL that asks the same question... http://diglloyd.com/blog/2015/20151020_1048-LeicaSL.html Excerpt.. "Key features highlighted in the product description below. Clearly video is a key feature in the SL, as its discussion comes early and amply in the description. It will be interesting to see whether the 24-90mm has “breathing” and/or is par focal." Jeff Link to post Share on other sites More sharing options...
edwardkaraa Posted October 28, 2015 Share #10 Posted October 28, 2015 You would be surprised how many manual focus old zooms are parfocal. My Contax 35-70 was parfocal for sure. I think most Contax zooms were. Link to post Share on other sites More sharing options...
eckart Posted October 28, 2015 Share #11 Posted October 28, 2015 Yes, that is my experience too. I would think the not being parfocal was coming up with the AF on cheaper lenses, Maybe dued by the fact of the self-regulating focus it felt not that necessary anymore and it was cheaper to produce. Link to post Share on other sites More sharing options...
psss Posted October 28, 2015 Author Share #12 Posted October 28, 2015 it would be great if someone actually knew....the SL is getting a lot of attention from people mostly interested in motion capture, so this would be a very interesting feature..... and there is no real grey area here, a lens either is or it is not, i am assuming that leica would have listed it as parfocal if it was.... Link to post Share on other sites More sharing options...
bab Posted October 29, 2015 Share #13 Posted October 29, 2015 Par focal must also have a point of poor to excellent, like a rating scale of one to ten so for 2500.00 where do you think that lens would fall? Link to post Share on other sites More sharing options...
psss Posted October 29, 2015 Author Share #14 Posted October 29, 2015 Par focal must also have a point of poor to excellent, like a rating scale of one to ten so for 2500.00 where do you think that lens would fall? that sony cine zoom is excellent...surprising optical performance....and the fact that it is parfocal AND and powerzoom AND FF for that price is actually pretty crazy.... Link to post Share on other sites More sharing options...
guidowi Posted October 31, 2015 Share #15 Posted October 31, 2015 It is critical for shooting video, and since the SL is marketed to this audience it is a relevant question. What is critical for shooting video is mainly a constant speed when zooming and the 24-90 loose one stop (2,8 to 4). About parfocal why not? The old stellar R 28-90 and 70-180 where both parfocal as well as all the Canon EF L and EF S zoom I use daily on the C300. Ciao Guido Link to post Share on other sites More sharing options...
graeme_clarke Posted October 31, 2015 Share #16 Posted October 31, 2015 My R 28-90 and R 21-35 are parfocal on my R9 DMR, and my M tri-elmar 28-35-50 (which is not a zoom lens but 3 focal lengths in the same unit) is parfocal on my M8. It is always useful to focus on the key subject at the highest focal length then zoom out to frame the shot. On my Sony A7R with a Novoflex adapter for the R lenses and an SRB one for the M, they are all - both the R and M lenses - a mile away from being parfocal and have to be focused at the chosen focal length using the magnification facility. It's a nuisance having to re- focus each time the zoom is altered. If an adapter alters the parfocal characteristics then I assume zoom lenses other than the Leica 24-90 for the SL will not be parfocal because they too will need an adapter. Unless someone knows better... Graeme Link to post Share on other sites More sharing options...
gvaliquette Posted November 8, 2015 Share #17 Posted November 8, 2015 My R 28-90 and R 21-35 are parfocal on my R9 DMR, and my M tri-elmar 28-35-50 (which is not a zoom lens but 3 focal lengths in the same unit) is parfocal on my M8. It is always useful to focus on the key subject at the highest focal length then zoom out to frame the shot. On my Sony A7R with a Novoflex adapter for the R lenses and an SRB one for the M, they are all - both the R and M lenses - a mile away from being parfocal and have to be focused at the chosen focal length using the magnification facility. It's a nuisance having to re- focus each time the zoom is altered. If an adapter alters the parfocal characteristics then I assume zoom lenses other than the Leica 24-90 for the SL will not be parfocal because they too will need an adapter. Unless someone knows better... Graeme WHAT??? The adapter is just a dumb tube between the lens' flange and a body's mount when the lens is not native to that body. How does it change the optical properties of the lens??? Guy Link to post Share on other sites More sharing options...
mjh Posted November 8, 2015 Share #18 Posted November 8, 2015 The adapter is just a dumb tube between the lens' flange and a body's mount when the lens is not native to that body. How does it change the optical properties of the lens??? By being just a tad shorter than the difference between the flange distances. Most adapters are. Link to post Share on other sites More sharing options...
wlaidlaw Posted November 9, 2015 Share #19 Posted November 9, 2015 You would be surprised how many manual focus old zooms are parfocal. My Contax 35-70 was parfocal for sure. I think most Contax zooms were. When you remove the rubber sleeve on Contax zooms, there are a number of adjustment screws exposed for adjusting the parafocality (if there is such a word ) of the lens. This is particularly important on one touch trombone for zoom/rotate for focus lenses. When it goes out of kilter, it is an expert job to get it right again. My 35-70 Contax lens went wrong and was sent to Contax UK's lens idiots, Johnsons Photopia. Not only did they manage to make it worse but they scratched the front element. Luckily as I was a Contax beta tester at the time, I managed to persuade Contax UK to pay for it to go to Malcolm Taylor to repair, which he did perfectly, if in his own sweet time. My current Contax 28-85, bought two years ago as new/old stock is perfectly parafocal. As digitalfx says, very useful for the very rare times I have shot video on my M240. I would have thought it matters far less with an AF lens apart from the noise of the focusing motor on video. Wilson Link to post Share on other sites More sharing options...
MediaFotografie Posted November 9, 2015 Share #20 Posted November 9, 2015 ...I tried the following thing with a demo model:in manuel focus mode the display shows focus distance (and dof); so I focus to 1 meter and change zoom range:dof changes significant, but the focus range remains constant! :-) greetings thomas Link to post Share on other sites More sharing options...
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