Parfocal lenses for LS300

Noa Put · November 30th, 2015, 04:34 PM

I was just doing some cameracomparisons between the gh4 and jvc so I checked, with my 42,5mm lens I can get about 1 cm closer to the object I"m focussing on with the jvc, with my 12-35mm lens at 12mm it's about the same. You have to know that even in 1080p the gh4 crops more then the jvc and when both are in 4K mode the jvc is significantly wider at the same focal length.

Dave Bittner · December 1st, 2015, 08:12 AM

Just an educated guess, here, but could it be an issue with the (clever) mismatch of the MFT mount and the Super 35 sensor? Is the distance between the lens mount and imager different than it would be with a standard MFT mount, MFT sensor combo?

JVC has this little comparison on their web site -

http://pro.jvc.com/pro/attributes/4k...35-MFT_150.gif

William Hohauser · December 1st, 2015, 10:53 PM

This really indicates a different construction. I would venture that a fully manual lens would have focal points at different places on the lens ring when compared between a GH series camera and the JVC.

Michel Rivest · December 10th, 2015, 05:57 PM

Quote:

Originally Posted by Dave Bittner

Just an educated guess, here, but could it be an issue with the (clever) mismatch of the MFT mount and the Super 35 sensor? Is the distance between the lens mount and imager different than it would be with a standard MFT mount, MFT sensor combo?

JVC has this little comparison on their web site -

http://pro.jvc.com/pro/attributes/4k...35-MFT_150.gif

According to this image, the distance between the lens & the sensor seems to be closer on the JVC than the Pany... I'm afraid that the only solution for a perfect parfocal option is only possible with only mechanic parfocal lenses (mostly manual) instead of electronic ones, and an adjustable back focus. Try to use a Tonkina 11-16mm or tamron 17-50mm lens (for Nikon or Canon) and a RJ adapter for MFT. The flange/back focus is adjustable and can help you a great deal to achieve parfocal capacity. Only downside, you can only use the manual zoom ring instead the zoom prime. This shows the downside of competitions between each manufacturers selling their own brand lenses with their cameras (and the lack of compatibility of their lenses & cams with 3rd party elements) vs. one manufacturer without any lens to produce & sell.

Steve Rosen · December 15th, 2015, 11:27 AM

I had a break this morning and took the time to do a witness mark check with three new Rokinon Cine prime lenses on my LS300 - the 24, 35 and 85. All three are native MFT mount.

In each case the focus marks on the lenses matched a measured distance to the film plane (sensor plane?) at 5 or 6 feet and 10 or 12 feet, depending on the lens. All, including the 12mm (which I didn't test for close distances because the focus range is so tight) focus accurately to infinity. (Again, the weird infinity marking on the 24 is something to be aware of - infinity is at the beginning of the scribed line, not at the symbol, and that lens will focus past infinity).

Additionally I tested my 35mm Summarit, 50mm Summicron and 135mm Summarit, Leica-R mount with Novoflex adapter, and the measured distances were very close, and all three focus perfectly at infinity.

So, the flange to sensor distance on my camera is accurate (which is a relief) - but I'm still in a quandary as to why my variety of zooms are so radically different on the LS300 than they are on all other cameras.

BTW - Just to add for those who might be interested... The Rokinons and Leicas match each other surprisingly well. The color and contrast is very similar (the 135 Leica-R is slightly colder), much closer than the Olympus 12-40 or Lumix 35-100.

Steve Mullen · December 26th, 2015, 04:56 PM

[QUOTE=Noa Put;1904049... with my 12-35mm lens... .[/QUOTE]

Noa, I'm wondering if all four electronic functions work with the LS300's manual controls:

Aperture -- Dial and Auto
Zoom -- Rocker
Focus -- AF and MF
OIS -- On/Off switch

Noa Put · December 26th, 2015, 05:27 PM

Yes, all work.

Noa Put · December 27th, 2015, 01:43 AM

Forgot to mention, when you zoom using the zoom rocker the camera crops on the sensor to simulate a zoom without visual quality loss, in my case this only works when I shoot in HD but not in 4K. When in HD if I have the 12-35mm on and leave it at 12mm I can zoom in using the rocker to about 22mm so the same should apply for a 12mm prime lens.

Steve Rosen · December 27th, 2015, 05:32 PM

Steve; I no longer have a 12-35 Lumix, but I do still have the 35-100. With that lens the exposure dial works well, but it is sluggish, which is the case with all auto lenses (I do have the Olympus 12-40 Pro, and it works exactly the same with that lens).

The auto-exposure works, but I can't tell you how well because I never use it except to get the iris in the ballpark for manual adjustment. It seems close though.

The rocker doesn't have any effect on the lens itself, there is no zoom servo in these Lumix lenses. As Noa says above, with the rocker set to the VSM it can dramatically change the overall focal lengths available to any lens. The 35-100 becomes something like 220mm on the long end at 43% VSM.

And, with the VSM set to 92% for the 12mm (on the Olympus), you get a VERY wide lens, something like a 9.5mm (there's a little vignetting, but it's not noticeable on shots with varied backgrounds - if it's bothersome, set the VSM closer to 80%, which is the MFT setting).

With the 35-100, and the VSM set to 95% (which is admittedly pushing it), that lens becomes a medium wide to very long zoom. Pretty cool, actually.

BTW - IOS works very well with the Lumix... In fact, too well - be sure to click it off when on a tripod (I forgot I even had it on last week and couldn't figure out what was going on in the viewfinder - that jello never showed up on the Pocket Camera).

But, as I said above, I've gone to mostly using primes. I bought a set of native MFT Rokinon Cines on sale, and using the VSM and the rocker I have a very sharp choice of manual short "zooms". For example, I can shoot with the 24mm, and at 100% VSM have a decent wide. Then I can zoom in to 43% (all this is in 1080 of course) and have the equivalent of about a 60mm... Or, if I think I might need the long end more, I can use the 35mm and zoom into about the equivalent of 85mm. The image quality compared to the Olympus and Lumix is immediately noticeable, even by non-peepers. And because these lenses cover the full sensor, you still get a little zoom even in UHD - enough to tighten a frame or slightly change a perspective. I love this feature!

November 30th, 2015, 04:34 PM	#16
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,510	Re: Parfocal lenses for LS300 I was just doing some cameracomparisons between the gh4 and jvc so I checked, with my 42,5mm lens I can get about 1 cm closer to the object I"m focussing on with the jvc, with my 12-35mm lens at 12mm it's about the same. You have to know that even in 1080p the gh4 crops more then the jvc and when both are in 4K mode the jvc is significantly wider at the same focal length.

December 1st, 2015, 08:12 AM	#17
Dave Bittner Regular Crew Join Date: Sep 2008 Location: Columbia, MD USA Posts: 27	Re: Parfocal lenses for LS300 Just an educated guess, here, but could it be an issue with the (clever) mismatch of the MFT mount and the Super 35 sensor? Is the distance between the lens mount and imager different than it would be with a standard MFT mount, MFT sensor combo? JVC has this little comparison on their web site - http://pro.jvc.com/pro/attributes/4k...35-MFT_150.gif

December 1st, 2015, 10:53 PM	#18
William Hohauser Inner Circle Join Date: Dec 2005 Location: New York City Posts: 2,650	Re: Parfocal lenses for LS300 This really indicates a different construction. I would venture that a fully manual lens would have focal points at different places on the lens ring when compared between a GH series camera and the JVC. __________________ William Hohauser - New York City Producer/Edit/Camera/Animation

December 15th, 2015, 11:27 AM	#20
Steve Rosen Major Player Join Date: Dec 2005 Location: Monterey, California Posts: 895	Re: Parfocal lenses for LS300 I had a break this morning and took the time to do a witness mark check with three new Rokinon Cine prime lenses on my LS300 - the 24, 35 and 85. All three are native MFT mount. In each case the focus marks on the lenses matched a measured distance to the film plane (sensor plane?) at 5 or 6 feet and 10 or 12 feet, depending on the lens. All, including the 12mm (which I didn't test for close distances because the focus range is so tight) focus accurately to infinity. (Again, the weird infinity marking on the 24 is something to be aware of - infinity is at the beginning of the scribed line, not at the symbol, and that lens will focus past infinity). Additionally I tested my 35mm Summarit, 50mm Summicron and 135mm Summarit, Leica-R mount with Novoflex adapter, and the measured distances were very close, and all three focus perfectly at infinity. So, the flange to sensor distance on my camera is accurate (which is a relief) - but I'm still in a quandary as to why my variety of zooms are so radically different on the LS300 than they are on all other cameras. BTW - Just to add for those who might be interested... The Rokinons and Leicas match each other surprisingly well. The color and contrast is very similar (the 135 Leica-R is slightly colder), much closer than the Olympus 12-40 or Lumix 35-100.

December 26th, 2015, 04:56 PM	#21
Steve Mullen HDV Cinema Join Date: Feb 2003 Location: Las Vegas Posts: 4,007	Re: Parfocal lenses for LS300 [QUOTE=Noa Put;1904049... with my 12-35mm lens... .[/QUOTE] Noa, I'm wondering if all four electronic functions work with the LS300's manual controls: Aperture -- Dial and Auto Zoom -- Rocker Focus -- AF and MF OIS -- On/Off switch __________________ Switcher's Quick Guide to the Avid Media Composer >>> http://home.mindspring.com/~d-v-c

December 26th, 2015, 05:27 PM	#22
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,510	Re: Parfocal lenses for LS300 Yes, all work.

December 27th, 2015, 01:43 AM	#23
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,510	Re: Parfocal lenses for LS300 Forgot to mention, when you zoom using the zoom rocker the camera crops on the sensor to simulate a zoom without visual quality loss, in my case this only works when I shoot in HD but not in 4K. When in HD if I have the 12-35mm on and leave it at 12mm I can zoom in using the rocker to about 22mm so the same should apply for a 12mm prime lens.

December 27th, 2015, 05:32 PM	#24
Steve Rosen Major Player Join Date: Dec 2005 Location: Monterey, California Posts: 895	Re: Parfocal lenses for LS300 Steve; I no longer have a 12-35 Lumix, but I do still have the 35-100. With that lens the exposure dial works well, but it is sluggish, which is the case with all auto lenses (I do have the Olympus 12-40 Pro, and it works exactly the same with that lens). The auto-exposure works, but I can't tell you how well because I never use it except to get the iris in the ballpark for manual adjustment. It seems close though. The rocker doesn't have any effect on the lens itself, there is no zoom servo in these Lumix lenses. As Noa says above, with the rocker set to the VSM it can dramatically change the overall focal lengths available to any lens. The 35-100 becomes something like 220mm on the long end at 43% VSM. And, with the VSM set to 92% for the 12mm (on the Olympus), you get a VERY wide lens, something like a 9.5mm (there's a little vignetting, but it's not noticeable on shots with varied backgrounds - if it's bothersome, set the VSM closer to 80%, which is the MFT setting). With the 35-100, and the VSM set to 95% (which is admittedly pushing it), that lens becomes a medium wide to very long zoom. Pretty cool, actually. BTW - IOS works very well with the Lumix... In fact, too well - be sure to click it off when on a tripod (I forgot I even had it on last week and couldn't figure out what was going on in the viewfinder - that jello never showed up on the Pocket Camera). But, as I said above, I've gone to mostly using primes. I bought a set of native MFT Rokinon Cines on sale, and using the VSM and the rocker I have a very sharp choice of manual short "zooms". For example, I can shoot with the 24mm, and at 100% VSM have a decent wide. Then I can zoom in to 43% (all this is in 1080 of course) and have the equivalent of about a 60mm... Or, if I think I might need the long end more, I can use the 35mm and zoom into about the equivalent of 85mm. The image quality compared to the Olympus and Lumix is immediately noticeable, even by non-peepers. And because these lenses cover the full sensor, you still get a little zoom even in UHD - enough to tighten a frame or slightly change a perspective. I love this feature!