Any 35mm adapters fit my 2/3" camera using a 55mm-diameter Fujinon 2/3" macro lens?

[Ralph Oshiro]

Sorry for the cross-post, but I'm DYING to know if this will work!!! I am trying to see if I can use any of the popular 35mm adapters made for smaller cameras if I buy this 2/3" Fujinon macro lens for my full-sized, B4-mount Sony DSR450. Buying this lens gives me a MOD (minimum object distance) of only 2.75" and has a front filter diameter of only 52mm. So, this SHOULD work, right?

Here's a B4-mount macro lens I found at B+H from Fujinon with a 52mm filter diameter!:

http://www.24framefilms.com/fmacro1.jpg

Fujinon MAF20B 20 mm f/2.0 Prime Macro Lens, Manual Focus and Iris with Bayonet Mount for 2/3-Inch CCD
B+H MAF20B description (http://www.bhphotovideo.com/bnh/controller/home?O=1886&A=details&Q=&sku=191219&is=REG&addedTroughType=categoryNavigation)
Fujinon Japan MAF20B description (http://www.fujinon.co.jp/en/products/tvlens/macro_lens/maf20b.htm)

Front filter diameter: 52mm.
MOD: 2.75" (70mm)
Iris: f/2.0-f/16, manual
Length: 4.1" (resulting in <6.85" min. length from rear element housing to GG)
Price: $5,417 USD

[vidled]

That should work, but I have to ask: can't you get the desired DOF with any of the lenses you have? What lenses DO you have now?

It seems an expensive way to achieve use of a 35mm adapter. There's got to be a less expensive way, surely?
I saw the adapters you posted in the other thread; I too was looking for a B4 adapter...unsuccessfully mind you.

[Ralph Oshiro]

So here's the standard Fujinon A20X8.6BRM 2/3" lens that I already own. The front-element, screw-in filter diameter is 82mm. But, I want to avoid going through all of this glass, and instead, mount the Funinon macro lens directly to my camera's B4 bayonet mount.

And no, even with the larger 2/3" imager in my DSR450, I can't get anywhere NEAR the shallow depth-of-field characteristics that ANY of the 35mm adapters are getting on the smaller 1/3" CCD cameras.

http://www.24framefilms.com/fuji.jpg

[vidled]

Ah okay. Sort of makes sense....if it weren't for the [relatively] huge cost of that macro lens.
Any chance you can get a cheap eBay-B4-lens and use it?

[Ralph Oshiro]

It seems an expensive way to achieve use of a 35mm adapter. There's got to be a less expensive way, surely?Well, vidled, that's EXACTLY what I'm trying to figure out! I don't see how I can get a diopter to work without a primary lens. In the other thread I posted something about Century's B4-mount "optical relay" but I have no idea what that is or how it works. At least with the Fujinon macro lens, I'm getting a REALLY high quality "relay" lens to image that GG. Plus, it's mechanically hard-mounted to the native bayonet mount on my camera (no adapter-clamped-onto-a-rubber-lens-shade contraption).

If the $5,400 Funinon does the trick, I'm still saving tons of money compared with the $27,000 P+S Technik Pro35 rig.

[Ralph Oshiro]

Any chance you can get a cheap eBay-B4-lens and use it?It's a pretty rare animal, it seems. I mean, how many guys do you know that has a pro macro video lens for their 2/3" Betacam or whatever? I searched high and low, and the Fujinon lens seems to be the ONLY game in town.

[Ralph Oshiro]

Just to make this perfectly clear . . .

I'M LOOKING FOR 35MM ADAPTER WITHOUT AN ACHROMAT TO HARD-MOUNT TO A 52MM-FILTER DIAMETER 2/3" BROADCAST MACRO LENS WITH A MOD OF 2.75"--WHO'S GOT IT?

[Ralph Oshiro]

Well, I just typed a lengthy e-mail to RedRock Micro and all I got was an automated reply--their FAQ, which of course doesn't answer my question.

I think one potential problem with the above set-up is that I've been reading that many of you are using your camra's zoom function to fill the frame with the GG image. This Fuji macro is a FIXED focal-length lens (20mm). So the GG distance would need to be adjusted somehow to fill the frame perfectly with the GG image size. The Fuji is able to focus at any distance up to 2.75" so focus shouldn;t be a problem, it's attaining the proper image size that may be the problem. But this should be easily solved if the GG unit had some sort of fore-and-aft focal plane adjustability.

[khmuse]

This is an interesting thread to me.

So just so that I am following your idea, you want to use a focus screen adapter with your DSR450, but want to avoid using a complex multi-element zoom lens and in its place use a prime instead.

Is this correct?

If so, I see a few problems, namely, the image size of the focus screen on the adapter would likely be way too small for any normal prime. I assume that is the reason that you are calling out a lens with a macro focus function.

Am I still on track?

Can this lens focus on a 22mm wide object and fill the full imager?

I have heard of "adapters" that are intended to use a 2 1/4" lens (like a Hasselblad) this might have a much bigger projected image and might be a much better choice for your application.

Have you tried just using a longer 2/3" prime to get shallower DOF? I would think that this would give much better performance than any focus screen adapter approach and would end up giving up much less low light performance at the same time.

Just my thoughts on this.

[Ralph Oshiro]

So just so that I am following your idea, you want to use a focus screen adapter with your DSR450, but want to avoid using a complex multi-element zoom lens and in its place use a prime instead. Is this correct?YES!


If so, I see a few problems, namely, the image size of the focus screen on the adapter would likely be way too small for any normal prime. I assume that is the reason that you are calling out a lens with a macro focus function. Am I still on track?YES, SIR, YOU ARE CORRECT!


Can this lens focus on a 22mm wide object and fill the full imager?Now, THAT is the $25,000 question!!! If the Fujinon macro lens achieves a 1:1 magnification (which I don't know that it does), would 22mm cover a 16:9 2/3" imager?

Thank you, Kevin, for replying to this thread. I've had no luck in contacting RedRock Micro. I would much rather purchase an already-engineered, and field-tested product, than try to hack together some homemade, DIY project. I was also thinking that I may have to go to a medium-format lens. So, now, all I have to do is figure out the answer to your last query, which I should be able to determine with a common lens-calculator thingy (perhaps either the Fujinon or Panavision online lens calculators?) I'll try this out when I get home from work tonight! Thanks Kev!

[khmuse]

...would 22mm cover a 16:9 2/3" imager?

I think that it would more than cover it, but let me bang out a bit of math to prove the fit.

I will post the numbers shortly.

[khmuse]

OK, this is just a straight trig problem.

Here is my math:

First convert the sensor data to diameter in mm.

25.4 (mm/in) * 2/3 = 16.93mm

Next find the radius.

16.93mm / 2 = 8.467mm

Next find the angle of a rectangle with the aspect ratio of 16:9.

16/9 = 1.778, Arc tangent of 1.778 = 60.642 degrees

Next find the opposite angle.

90 degrees - 60.642 degrees = 29.358 degrees

Now knowing the hypotenuse (8.45mm) and the included angle (29.358 degrees) find the two sides of the triangle.

Adjacent = hypotenuse * sine of the angle = 8.45mm * (sine 29.358 degrees) = 8.45mm * .49 = 4.143mm

Opposite = hypotenuse * cosine of the angle = 8.45mm * (cosine 29.358 degrees) = 8.45mm * .872 = 7.365mm

So, the area of a sensor with an aspect ratio of 16:9 that would fit within a 2/3" sensor footprint =

7.365mm * 2 = 14.73mm

4.143mm * s = 8.286mm

To check the above 14.73mm / 8.286mm = 1.778

So, yes it would easily cover it assuming a 1:1 factor by 1.494 times.

(22mm / 14.73mm) = 1.494

[Barry_Green]

2/3" sensors aren't nearly that big either. According to the Panavision NZ DOF calculator, a typical 2/3" 16x9 chip is about 9.6mm x 5.4mm.

[khmuse]

The numbers quoted by the Pana NZ calculator look more like a die circle area for a 1/2" not a 2/3" sensor, but in as much as there isn't a "standard" I guess you can call anything a 2/3" sensor if you want.

Obviously, in this case, it would be much easier to just "know" the sensor area than to have to "derive" it via mathematics but this seems to be a specification that is often not easy to obtain.

[Barry_Green]

Well, the point is, a 2/3" sensor isn't called a 2/3" sensor, it's called a 2/3" TYPE sensor, and the calculations are based off of the rectangular area that gives comparable image coverage as what an old 2/3" diameter tube camera would have delivered(!)

No sensor (1/4", 1/6", 1/2", 1/3", 2/3" etc) is anywhere near as large as the actual mathematical description that they seem to imply.

[vidled]

Ralph, PMed you a pic of a SLIDE FILM adapter for a 2/3" cam.
This might work too for a 35mm adapter?

[khmuse]

Just pulled in the owner's manual from sonybiz.com and as suspected, the imager data lacks any reference to the sensor area. I will research the replacement CCD block to see if it gives any clue to the actual area.

The use of the word "TYPE" certainly gives them more than a bit of a "fudge factor". I think I have a data sheet for an old Nuvacon flying beam tube somewhere. Perhaps they have an active area listing in their specifications, that could be applied as a "factor" to determine actual area versus "TYPE" diameter.

[Ralph Oshiro]

Thanks for all your help guys! Really appreciate it. I hope I can figure this out somehow!

[khmuse]

Hey Ralph,

Do you happen to know anyone at Sony's service department that might be willing to provide a bit of info on the CCD block? That would end the speculation and calculations and give you the data you need.

[Ralph Oshiro]

Maybe. I need to call around. Thanks Kev!

[Ralph Oshiro]

Okay, here's what I get from Fujinon's field-of-view calculator:

Fujinon MAF20B 2/3" macro lens givens (calculator outputs field-of-view dimensions):
MOD: 2.75" (70mm)
Focal length: 20mm

http://www.24framefilms.com/FujiCalc2.gif

This results in a field-of-view of 24mm (W) x 13mm (H). So, I'm in, right?

[Ralph Oshiro]

Oh, by the way . . . Did I choose the right "Camera Format" for the non-ratio-converted Fujinon MAF20B, when stuck onto my native-16:9, 2/3" CCD SD camera?

http://www.24framefilms.com/aspect.gif

[khmuse]

Hey Ralph,

The calcs from the Fujinon site seem to indicate that you are in good shape with this lens. You would only need to make certain that the focus screen is at or beyond the MOD requirement for that lens.

It still seems to me though that this is an expensive solution and it would also seem that it will be difficult to test without a considerable financial investment up front.

Are you fully convinced that you need ultra shallow DOF compared to what a longer prime, full open would achieve on your 450? Is the resolution loss worth the easier selective focus?

Just curious.

[dan]

Are you fully convinced that you need ultra shallow DOF compared to what a longer prime, full open would achieve on your 450?
I think I remember this one being discussed before (the difference being the field of view as in tight spaces).

[jsb23]

I dont know if this is off topic or not, sorry if it is.
Would the Redrock M2 adaptor fit and work on a 1/2" CCD camera,
i.e. the sony xdcam PDW-330 or the 350.
Would it work to the same level as it does on the 1/3" models.

[Dino]

Rezfactor, this looks like a brilliant idea. I'd like to try the Fuji prime and a Brevis 35 with my DSR-450. Please let me know if you make any progress and get to demo that lens with any of the 35mm adapters.

Jeff Regan
Shooting Star Video
www.ssv.com

[joe 1008]

What effect does the mayor aperture of 2/3" primes have on the DOF? Does it create a much more shallow DOF or is the result not that impressive as it is with primes for 35mm sensors?