Guys, as promised Mike Tapa of MTF Services came through with a GY-HD100-250 Nikon lens-mount adapter for us to do a little comparison against the Zork adapter that I've had here for a few months now.

I'm no genius but I have been dorking around with the Zork and Nikons for long enough to know some of the issues we face while choosing this path.

1 - fit. The first Zork that I received was a little sloppy at the Nikon/Zork connection. Zork quickly replaced this "rogue" adapter and now we've got no problems. The MTF fit snug right out of the box.
2 - build. You'll see from the images I took. The MTF seems beefier.
3 - design - It's just a simple adapter. No glass, no electronics. Basically it's a spacer. But then you go and use one for a while and you learn the two adapters are actually pretty different. Mike gave a lot of thought to his design. It makes better sense where he put the aperture indicator. You'll see from the photos.
4 - RED FLARE. This I do not have the answer to, yet. But I plan to do some comparison shots this upcoming weekend. Should be interesting.

I put two pages together with some rollover images and some text for anyone who's not quite sure about these things. Please pardon the typos. It's late and my eyes are crossed. Just wanted to get this done tonight.

Here's the comparison http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/NikonAdapterCOMPR.html#

Thanks Eric for the report and ongoing comparison of the Nikon adaptors. I look forward to the "rockets red glare" test and your conclusions. The MTF is looking good so far. I thought one of the differences was that it had more black finish on the interior to theoretically help block reflected light. In the pics they look pretty similar in that department.

You are right Sean, they look the same considering bare aluminum flanges. I am going on what others have said about the red flare and where it comes from. If it is the aluminum ring, I can't see how the MTF will cure it. However if you look at the cylinder type sleeve that protrudes into the JVC you'll notice the MTF sleeve is longer. I don't know. Testing will tell. And I know exactly how to produce the flare..

By the way Mike tells me not one person has ever reported any red flare while using his adapter. While the Zork rep was well aware of it and even suggested the black magic marker solution - which did not work for me.

OK I've chased this red flare problem into a corner. Still don't know how to fix it, but at least now I know a little more about it:

What: Lower 20% of frame turns translucent red.

When: While shooting high contrast subject matter with the whites over exposed. Neither aperture, zoom, or focal range matter much. Once it shows up, it's there.

How much: The more over exposed the image, the worse the flare.

Why: Need a genius here. I am not a genius.

Solution: So far, "Go away from the light"

How to avoid: Use your zebras. Do not overexpose any part of your image.


Unfortunately, as you can see from the frame grabs below, BOTH the Zoerk adapter, and the MTF adapter produce the same red flare. The images were taken of exactly the same subject - the back of 600w flood light with flat black barn doors, aimed at a white wall. Exact same lens/camera/subject/settings for every example shown. Each image is named appropriately - Zoerk_RedFlare-100shtr.tif = Zoerk adapter, Red Flare example, shutter speed used in shot. All shots at f2.8, but you can get this flare at any aperture.

NOTE: The examples shown here are extreme cases. In fact I worked hard to capture this condition at it's worst. Although I definitely have had this show up in usable, and in fact "used" shots, I have never seen it this bad out in the real world. The most consistent conditions where it shows up for me is while shooting surfers in bright sunlight - where you need to let the darks of the water and surfer pour into the lens, but then end up blowing out the white water as the wave suddenly crashes. When the white water over exposes the bottom of your frame turns red.

Zoerk adapter Red Flare sample images:

Zoerk_RedFlare-10,000Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-10000shtr.tif)
Zoerk_RedFlare-4,000Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-4000shtr.tif)
Zoerk_RedFlare-2,000Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-2000shtr.tif)
Zoerk_RedFlare-1,000Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-1000shtr.tif)
Zoerk_RedFlare-500Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-500shtr.tif)
Zoerk_RedFlare-250Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-250shtr.tif)
Zoerk_RedFlare-100Shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare-100shtr.tif)




MTF Services adapter Red Flare sampel images:

MTF_RedFlare-10,000shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-10000shtr.tif)
MTF_RedFlare-4,000shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-4000shtr.tif)
MTF_RedFlare-2,000shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-2000shtr.tif)
MTF_RedFlare-1,000shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-1000shtr.tif)
MTF_RedFlare-500shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-500shtr.tif)
MTF_RedFlare-250shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-250shtr.tif)
MTF_RedFlare-100shtr.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/MTF_RedFlare-100shtr.tif)


Real world shooting problem/example: Challenging exposure to set. Dark water, dark surfer. Everything was going well, until the wave broke..
Zoerk_RedFlare-Surfer.tif (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/Zoerk_RedFlare_Surfer.tif)


In addition to the Red Flare problem which occurs mainly on the bottom of the frame, sometimes, when you get the light just wrong, there are other red flaring problems that randomly, rarely occur. Follow this link to a short clip showing one of these outer body experiences first hand.
Rack_Focus_FlareClip (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/Zoerk-RedFlare/NikonAdaptr_RackFocus_Flare.mov)

Uh, oh, smoke coming from keyboard

.sorry, this mac is on crack

Eric,

I was experimenting with a couple of 35mm lenses a nikon and a tamron and tried it directly on the jvc. I havent made a zork like adapter yet just a plastic ring that acts as a spacer to maintain flange distance. And somehow while tweaking the lenses, lo and behold, a bright reddish/ orange flare showed up similar to the images you posted.

So i guess its neither of your lens mounts but more to do with the lens aligned in a certain way and hitting the ccd or it protective glass, that i believe has a special coating, that produces this.

Ted,

ps. how much is the mtf adapter ? can you help me acquire one?

No problem Ted, they are listed here: http://www.mtfservices.com/products/lens%20adaptors/lensadaptors.html

Mike's a pretty cool guy. You can email him directly at: mike@mtfservices.com


That'll really stink if this is unavoidable. Let's hope it's not true.

Hi Eric, Thanks for the sterling work you are doing to pin this problem down.

I have had a look at your images, and to me it looks like something I have seen before in my time at Optex.

I really dont think its an adaptor issue but more to do with the beam splitter in the camera.
The effect I have seen in the past was a common problem with all three chip cameras where top and bottom of the image had a different hue.(slightly blue and slightly pink) cant remember off the top of my head which colour was bottom though.

We used to deal with a lot of Toshiba Mini cams (TU48 or TU63) and our electronics guy could get into the engineering menu to compensate for this.

Point a camera at a white wall with no lens, see if you can spot it.

In the meantime, I will make some calls and let you know if I discover anything.

Thanks Eric for the links,

Mike, I sent you an email regarding your adapter. I plan to mounta 17mm nikon compatible lens on my jvc to replace the fujinon as relay for a lens adapter i made.

Cool Mike. Sounds very interesting.

I have a strange feeling/memory that I actually might NOT have seen this flare while using the 300mm 2.8. I have a few Nikon lenses other than the 80-200 2.8ED which I used for the shots in last night's tests. Tonight I will test them all, in the same exact shot. This should tell us more, I hope.

Thanks for jumping in Mike.

I'm having the exact same problem with my 80-200mm Nikon on an HD100, using a self-made adapter (that looks, necessarily, very much like the MTF and Zoerk). I actually thought, for a while, that it was some problem with my adapter, until I came across this thread. So I emailed Eric yesterday; turns out he just was about to go ahead with his tests (thanks for the quick reply, btw).
In my case, the problem is not exclusively related to overexposure, although it seems to be more apparent then. Same as in Eric's experience, zoom, focus and iris setting do not have a big influence. I have pretty much ruled out stray light hitting the lens as a culprit.
Here are some frames that show the effect in rather low key exposures:

http://www.flickr.com/photos/24672974@N07/2334194692/in/photostream/

Also, it's not always just an out-of-focus flare but often what seems like a sharply rendered secondary image. In this example you can clearly make out twigs and leafs in the 'flare' (note that the extreme blue fringing is an unrelated issue):

http://www.youtube.com/watch?v=zunxmDUHfH4

(sorry for the youtube thing, it's just that my internet connection is pretty pathetic right now, I'll post some higher res examples later)

So, I've been thinking long and hard about this and ,frankly, I'm drawing a blank here. However, I think it's safe to discard the 'reflection from the bare metal flange' theory. The flange (at least in my adapter) isn't even exposed to the light path. l would agree with Mike that this is an issue to do with the camera internal optics. Maybe a reflection within the beamsplitter that occurs at such angles that only the 'red CCD' is hit. (The color of the flare is exactly the same every time and seems to me very close to a spectral red)

Will be very interesting to find out if this only occurs with telephotos.
Ted, what kind of lenses did produce that flare for you ?

I also have a few tests in mind that might shed a little more light on this, but it'll have to wait a little , as my camera needs some surgery right now.

On other threads I've seen posts by a guy who seems to be very knowledgeable about optics. His name is Ryan Damm. Maybe it'd be a good idea to invite him to give his 2 cents to our problem. I'm not a regular forum user and wouldn't know how to do this.

OK I've tested every Nikon lens that I have here. They all produce the exact same red flare - with either adapter being used. So I agree, maybe this isn't an adapter situation after all. However tonight's findings are far from discouraging.

Following Mario's clue about the red leaves in his image, I became curious about identifying exactly what part of the image it was that was being reproduced, or split. It took a bit of dorking around but finally I discovered it's not anything "IN" the frame that is getting reproduced at all. The reflection is actually coming from just BELOW what's visible in the frame. I stuck tiny pieces of gum eraser to the edge of the flood light's barn doors, then panned upward from below until they were out of frame for a bit. As you will see in the linked .mov file, an upside down phantom barn door suddenly appears within the red flare - long after that same edge went out of the frame being shot..

You wanna' know why? Well, don't ask me. It took me six months to memorize my paper route when I was a kid and there were only nine houses on my block...

Here's the Phantom Barn Door video (http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/MTF-RedFlare/BarnDoorPhantom.mov)


With all the fumbling around with this red flare chasing and lens switching I have learned a bit more about how to work with it, and even how to avoid it. Turns out it actually IS avoidable, by stopping down the lens and compensating with shutter. I know I said before that aperture doesn't matter, but let me remind you please about the paper route...

At 2.8 with both ND filters on and shutter speed ranging from 1/2000 and below, shooting this extremely bright white wall with a flat black barn door in front of it, this red flare situation is in it's element. You just can't avoid it. BUT as you stop the 80-200 down, and then compensate by removing ND and slowing shutter to equal the exposure you just had, the red flare DOES drastically reduce (in both size into the frame, and brightness). With both NDs off, the shutter set at 1/60 and the aperture at f16, I couldn't get the red flare to occur anymore. Now of course we'll have to test the 80-200 at f16 because that's got to be way past it's sweet spot, but perhaps only this extreme case would force you to go that far down. I did notice the red flare had been reduced by about 65% once stopped down to f8 from f2.8. I bet in real world conditions you wouldn't get flare past f8, in average exposure ranges.

Lastly, Mike, your idea about eliminating any hue seen while shooting a white wall, via the menu settings, is actually a suggestion I have heard before - from our NY friend Sean Adair. He's probably reading your suggestion while reaching for a baseball bat to come gently remind me that I should have done this months ago. Sorry Sean. I dropped that ball. I'll check it tonight..


NOTE, it has been my finding at least, that the flare problem does not occur by simply aiming the lens at a high contrast, brighter than hell surface. At least with my rig, the flare only kicks up when you happen to aim the lens at just the wrong angle to the source. I'd guess 80% of the time shooting that same light source you won't see the flare. It's just those times that you do see it, that we are talking about here. I would hate to discourage someone from using these lenses on their JVC because we are discussing it in such detail here. Believe me, and like Mike told me in an email a few months ago - not one user of his adapters for this JVC camera has ever even mentioned red flare. So by all means, "Go long..."

having put a canon 50mm 1.8 onto my camera I've also seen a flare, but usually on the top of the frame. so I'm going to say this is about a reflection between the rear of the lens and the front of the CCD block. since the 35mm lens wasn't designed to deal with a reflection from glass, its coatings are absorbing the reflection. I would also suggest that with the greatest of care, perhaps painting flat black into the silver interior of the lens mount might help a little, but if its glass to glass.. your stuck. perhaps a slight shift in the lens to make it NOT parrellel with the CCD would push the reflection out of frame. I've done this with some filters in front of the lens when I saw the lens in the filter. tilt the filter to force the reflection away. while this could cause problems, it would be interesting to try if there was a way to figure out shimming the lens a thousand or 2 one way or the other to make it go away.

Interesting findings, and I think you guys are zeroing in on the problem.
Why not invite MTF and Zoerk to comment on the examples and discussion so far? The Optics guy on the forum can be sent a personal message through the forum by finding him on the members list (menu above), and copying a link to the thread.

The shape offscreen that Eric documented so vividly with the tiltup eliminates a lot of possibilities (including the chromatic shading adjustment mentioned that the 200 series cameras can do). I still think that running that calibration IS likely to reveal some room for improvement overall though.

I think it's pretty conclusive that there is some sort of internal reflection taking place between the rear element of lens and the camera ccd.

Changing the alignment of the lens seems to me could cause other issues (like losing sharpness on one side). Also, it seems it might just move the problem, picking up flare from another place. But with the ghost image coming from OUT of frame, it seems likely to be some other element than the ccd (which should just have the main image hitting it). This could be something in the camera as well - in fact that might be even more likely. Ready to take that sharpie into the flanges INSIDE your camera?

This is also likely (that it isn't the ccd reflecting), when you think about it, since the lens is bringing in a much larger image than the imaging ccd. There is light for a 35mm frame hitting all around the sides of the ccd, that a lens for a 1/3" ccd won't produce. Could this larger area be masked at the adapter stage? It will be a softer edge further from the ccd, but more predictable than trying to mask in front of lens, which will change with zooms, and is likely to be even softer (recipe for some vignetting). I suppose you could experiment with a hole in black construction paper to create a mask mounted temporarily inside to limit the image area before it goes into the camera (or it may sit better right inside the camera...). I notice that there are several filters before the ccd. The ND wheels off, still has a clear element, and there is a clear element in front of that.

Recognizing the problem, and avoiding it in the field, as well as minimizing it when it can't be eliminated possibly will be the only approach. There are already many situations simply unacceptable for the best images, and a pro cinematographer builds up quite a library of problem scenarios to avoid.

The prior knowledge is really important though, since finding out the problem after the fact if you aren't monitoring carefully, could be pretty inconvenient.

It makes sense that stopping down the lens helps - less light bouncing around in that area - the electronic shutter only works AFTER the fact.
Keeping the exposure down with ND filters instead of shutter might help in some cases too.

It seems like this is pretty limited in actual scenarios. If hot spots are essential for your subject, like the white breaking waves, you could try underexposing (with a setting to minimize contrast in gamma and avoiding deep blacks). Then bring up dark/mid areas in post. The details in waves would be an added bonus. A low contrast filter would probably help in these situations as well. For several of the examples, I think this would help the overall shot.

There's also post correction of the red with a software mask and CC, but that would be pretty annoying work given the way the effect can change, move and take on shapes....

I think the "red flare issue" is not a result of the adapters. In my view the reason is the difference in the diameter of the pictures built by a standard 1/3 inch TV-lens and a photo-camera lens designed for 35 mm film. In the first case the diameter of the picture is some 6 mm, while in the case of the the "Nikon's" the diameter is 43 mm. As a result of the much bigger picture area, quite an amount of light is focussed besides the the active area of both, splitter and CCD-chip. This "vagabonding" light may cause reflections somewhere inside the video camera, which finally causes the red flare effects you have found. A measure to avoid it would be the inclusion of an aperture inside the adapter, which narrows down the light beam to the active area of splitter and CCD chip. May be you can test it with placing some black paper made apertures inside your adapter.
Joachim

Sean, Mike Tapa (who responded here) IS MTF. I spoke with the US Zork rep (dealer/importer) about this flare problem a while back. Both he and Zork are aware of it (by the way, "Zoerk" spelling seems open to interpretation. Even Zork spells it both with and without the e). In fact it was Zork who told me the reflection was coming from the aluminum flange, and that I should blacken it with a marker (which I did, but it didn't seem to help). Good insight and ideas. I think it's time to get creative. Oh and I did look into the hue situation last night, against a pure white surface. The image I see is pure, even white, no matter the exposure (at least with the Nikons).

Joachim, thanks for the knowledge. You and Sean seem to be on a similar page, which sounds great because I have not heard these points before. It's such a great combination, the JVC and these telephoto lenses. I hope we can work this nagging detail out.

I'm having the exact same problem with my 80-200mm Nikon on an HD100...
On other threads I've seen posts by a guy who seems to be very knowledgeable about optics. His name is Ryan Damm. Maybe it'd be a good idea to invite him to give his 2 cents to our problem. I'm not a regular forum user and wouldn't know how to do this.

Mario, I emailed Ryan through the DVinfo channels. Maybe he'll chime in

The more I think about it, the more convinced I am that the 35mm sized image being projected in there is the problem. In some respects you could consider it an adapter problem, since it is a tool for the job. A mask or perhaps even a paper cone which cuts off the unused outer parts of the image, and blocks the image area from reflections could eliminate it.
Since there is a glass element in front of the ccd and nd filters, it is likely that this is the surface getting the reflected images.

We are definitely on the same track Joachim! (see my previous note).

Sean, I think you hit the nail on the head.
I was just about to jump in with that theory, but you beat me to it.
Tomorrow, Im going to look at the design to see if I can incorporate a built in mask.

Tonight, I just sold the last adaptor of this batch, with the next batch arriving at months end-too late for the redesign.
If the mask idea works I may even be able to have some made up to send out to anyone already using my adaptor.

I should come to this forum more often instead of wasting precious hours watching F1 !!

oops, sorry, you to Joachim deserve credit if the idea works

Cheers people.

Mike, I'm game to dork around with a black paper version of a mask here in the mean time. Mario sent me a detailed email (with images) explaining what might be happening with the excess 35mm image area, the beam splitter, and the resulting phantom reflections. It seems we're all on a similar page. Or, you guys are on a similar page - I'm just reading along.

T E A M - together, everyone, achieves, more


and by the way Mike, MotoGP not F1. Too many tires..

Mike,
I have a feeling that a built-in mask will not universally work for all lenses. For any given lens the correct mask might depend on the location and size of it's exit pupil.

Hi all,

Great discussion and thread -- good to see lens adapters have made such progress in the past year or so. My two cents -- the masks will probably solve the problem, at least the "lower third" red flare.

The flare is almost certainly a true image from the taking (Nikon) lens being reflected internally in the JVC's optics, because it's in focus and approximately the same size as the overall image -- suggesting the beam path isn't significantly longer than the light that should be hitting the CCD's. Also, it's an image, not some nondescript flare (according to the lower-barn-door test, and the monkey frame pulls), which suggests it's not a reflection off of the imaging optics -- it's a reflection off a flat surface (very likely the inside of the beam-splitting prism). (In the surfing shots, it might be the sand.)

I could write more (and might, when I have more time). In the meantime, some worthwhile reading:

en.wikipedia.org/wiki/Telecentric_Lens
en.wikipedia.org/wiki/Three-CCD

When you take into account the fact that the 35mm lenses will always cover a larger area than the beam-splitting prism, and the fact that the rays that strike the edges of the frame aren't perpendicular (as would be in a telecentric design, which is usually required by the 3CCD design), some stray rays are able to bounce around inside the prism. The good news: looks like they're non-imaging rays anyway. You'd see this much worse, by the way, if you got a non-telecentric, non-retrofocus medium- to wide-angle lens (where the peripheral rays are extremely slanted). Then, it might not be fixable.

So -- hopefully it works. And thanks for the vote of confidence -- I have to confess to falling off in my posts in the last year; I'm getting a Red so adapters aren't as mission-critical. Though I do have an exciting new project... 4-dimensional imaging (long story -- for fun, check out www.refocusimaging.com, a friend's startup). I'm in the early stages of a conceptual project that would use computational imaging -- way cool.

PS -- you may actually want a double mask: one right at the beam-splitting prism, and one further out to catch stray rays... it occurs to me that a double mask will effectively vignette the incoming rays -- if done properly you can vignette the flare-causing strays while leaving the imaging rays mostly alone. A single mask (particularly at the prism) probably won't do it.

Hello again.

Looking at the design of my adaptor again, I propose to incorporate a mask but not close to the prism as this will not solve the problem, as Ryan and Mario pointed out
Ideally the mask needs to act as an aperture close to the rear element of whatever lens is being used. However, as the physical position of the rear element will vary depending on which lens you have, it looks like I will have to try a compromise position for the mask.

Approx 17mmØ @ around 9.5 to 10mm in from the mounting face of the Nikon mount.

I will let you know how I get on.

It turns out you ideally want to mask it in both places -- the light leaking through is probably stray rays from near the outside of the aperture (which is why it disappears at small f-numbers) that then strike the beam-splitting prism at an oblique angle.

The mask behind the back of the lens will help -- but because (as an earlier post pointed out -- sorry, I can't remember the cite) it's not near the focal plane, it will effectively be out of focus. This might be okay -- again, you're probably talking about stray rays near the edge of the aperture, so if you clip them correctly, you might be occluding the rays you want to occlude.

The mask at the prism block will do part of it, but again, I suspect the light being admitted is along the prism block, so you can't block the bad light without blocking the desirable light.

Finally, a matte box in front of the lens will do the absolute most. Keep that light from falling onto the lens in the first place, and you're in the clear. Again, the fact that the light appears not to be coming from inside the frame is the saving grace, here.

Are there any other flares that are concerning, or is it just the red flare? (Incidentally, it's red because this light is coming in at such an extreme angle, the dichroic mirrors don't reflect it in the typical, designed way -- so all the stray light is ending up on the red sensor. The wikipedia page on 3-CCD cameras has a pretty decent diagram, you can see that the prism block is offset.)

mike, i think a rectangular (16:9) mask would be more effective than a round one.
I believe Eric is doing some tests with different size masks already.

Sorry guys, I'm in NY right now NOT doing anything related to video. In the last days rushing to complete a framing job before I left I did not have time to experiment with creating a paper mask. I will get on that starting this upcoming Tuesday.

While on the subject of using this camera, these adapters, and those lenses - I thought I'd share my most recent exercise. A few times now, quite appropriately, the issue of focusing, and smoothly panning while using such telephoto ranges has come up during talks about using our cameras this way. This past Sunday I went out for more practice - facing the red flare problem, the steady panning challenges, and follow focusing. It was a horrible shoot, aiming directly at the sun, but that's what I had to deal with on this day. There IS some red flare, but I did well to avoid it most of the time by staying above f8. Thanks to the testing here, I was quite happy to get such little flare, especially considering I was shooting the high glare of water AND shooting toward the bright sun. As for the steady tripod work, I didn't nail that all the time either - but I have made some progress. I can't take the credit though, it's the new tripod..

http://www.reelsense.net/QT/Kiteboarding/Wadell_3-16-08.html

Eric - I really enjoyed your CA coastline video...I mean really...thanks.

http://www.Reelsense.net/QT/GoforIT/GoForIT.html

Oh, and that link above - have you been like, practicing or something? Nice camera work on a tough shoot!

OK guys, back to the red flare problem.

I have gone at this a few times by now and not gotten anywhere. Tonight though, I really tried. I created a mask from black paper, cut out a nice 16x9 hole in the center and fastened it to the inside of the adapter. I wasn't so concerned with size at first - just wanted to see what effect cutting all that unused image out of the equation would do. I set up the same light/barn door scenario and tried it out. Flare was still there, looking and behaving exactly the same. So I pulled the adapter and lens apart again and closed up the 16x9 opening in the mask. The first opening in the mask was about 3/4" wide. The second was about half an inch wide. Same result, flare everywhere just like before, only now the overexposed areas weren't so over exposed. Third time proved NOT to be a charm either. Finally on my fourth go around, which gave me a ridiculously small 16x9 opening in the mask (@1/4"x3/16"), the overexposed situation that I created so well with the 600 watt light shining against a white wall was no longer overexposed at all. But the red flare was still there, exactly the same look, size, and behavior.

I was really looking forward to reporting good things, as all the theories on this problem make great sense. But I think we might be barking up the wrong tree here. Did I do something wrong? Any more ideas?

I have a Zoerk adapter and I've seen the same redflare specially when tilting with a 28mm Nikon lens. Have anybody asked to Zoerk/Mtf about this phenomenon?

Saul, I organized a few pages on this subject which follow the original adapter comparison that I linked to on page one of this thread. Mario Cater sent me some homework he did on this subject, which I put together here on page three of the test http://www.reelsense.net/HD-200/JVC-Nikon_Adapters/NikonAdapter_RED_FLARE.html

I plan to have another go at this tonight. Maybe give it a whirl yourself. Hopefully you'll have better luck.

I have seen the link of Mario's work. Very interesting.Let us know about your new experimentation.
Thanks.

I tried alot of masking and shapes inside the adapter but the easiest way to get rid of the red flare is to take your camera with your nikon lens installed, make sure to use a filter or polarizer on the lens. Hook up your camera to a decent monitor or HD TV, create the conditions to get the red flare, now take a business card and begin to cover up the lens. Find the spot where the red flare disappears and this will be how much the lens has to be covered. If you go too far, you will see on the monitor the image will start getting darker. I have found that its about 1/3 of the lens that has to be covered. This works on my macro 60mm Nikon, 70-200 Sigma, 80-400 Nikon, 18-70 Nikon. What I have done is, to keep the one polarizer set up this way and just use different rings to fit the lens. The images produced with this combo sure beats out the standard lens.
Hope this helps you out until someone comes along and makes an adapter that really works in the outside world.

Doug Harvey

I had a similar problem when I had an adapter built for mounting a Tokina 150 to 500 lens on a Sony camera in the mid 90's. Under certain light conditions I had a purple colour on the bottom part of the image which seemed to be light reflecting inside the lens some how that the camera doesn't like. Like Doug mentioned I found out if I moved my hand in front of the lens at a certain point I could get the purple colour to disappear. My fix was to make the objective lens smaller by putting a cover made of hard plastic with a smaller hole over the end of the lens. I lost some light but it fixed the problem. Later I mounted the same lens on a XL1 and never had the problem with the purple colour even with out the plastic cover. To me it appears that some cameras have a problem with mounting 35mm lens on them.

Gordon Hoffman