just got my mits on a 1.5x anamorphic adapter

M

matt9b

Well-known member
Not sure if I posted this in the right place -

I just got my hands on a 1.5x anamorphic adapter, and after unstretching the image by 1.5 , everyone looks a little fat to me. Is this not the right ratio for a 1.5 adapter?

I thought 1280x720 becomes 1920x720, is this not right? Perhaps my maths is wrong or there is something I'm missing...

Footage still looks great but still, would be nice to get it right..

If anyone can enlighten me that would be great! Thanks :)
 
The big question here is: What format are you filming in? 1280, 720, or some odd rez? The format you are in is what you need to base your end calculations on:

With a 1.5 you get:
1080 - 1920 x 720
720 - 1280 x 480
480 - 720 x 270 (I think)
 
Don't forget to check your pixel aspect ratio! If you shot square and the stretch is done on a nonsquare timeline, that'd make people seem "a little" wide.
 
Cheers guys, yes this is what I'm doing.. so thanks for confirming its right :) but people are still looking a bit fat! I'm shooting 720p on a GH-1. The stretch is done in Vegas by changing the pixel aspect ratio to 1.5

I've also tried using the 'deform' effect to stretch the image horizontally by the correct amount (or squash vertically), but whatever I do, they look a little fat. I can of course tweak it using my eyes, but would prefer to get the actual figure right.

'correct' x1.5 stretch that makes people look fat: http://www.facebook.com/video/video.php?v=178392307958&ref=mf (vimeo: http://www.vimeo.com/7251146)
'incorrect' x1.25 stretch that makes people look right: http://www.facebook.com/video/video.php?v=178269702958&ref=mf

What do u guys think? Do I have the figure wrong? Is this in fact not a x1.5 iscorama 36 anamorphot?

Thanks :)
 
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Is it possible that this is infact a iscorama 36 1.333x adapter instead of a 1.5x ? do such things exist?

It has a serial number and ISCORAMA on it but thats it.

Thanks
 
Your footage looks correct to me at 1.5 and while it is more flattering to the faces at 1.25, it looks stretched to me. In close up, you may have a case of the "anamorphic mumps" - google it. It's distortion caused by the lens design which is trying to look best at middle distances.

Obviously you need to shoot a test. Make a chart with a circle on it, and also an oval that will be wider than it is tall by a factor of 1.5. Put some squares and rectangles on there too if you have doubts about your oval. Light it evenly, shoot it square to the wall on a good tripod.

Let us know how it goes.
 
Make sure your output/export/whatever is set to square pixels 1280x480(if exporting for inet), and your end result should be fine
 
Jean Dodge said:
Obviously you need to shoot a test. Make a chart with a circle on it, and also an oval that will be wider than it is tall by a factor of 1.5. Put some squares and rectangles on there too if you have doubts about your oval. Light it evenly, shoot it square to the wall on a good tripod.

Let us know how it goes.
Click to expand...

Cheers Jean, you read my mind! I have already prepared the ovals; an exact 1.33 stretched circle and a 1.5 stretched circle. I'm looking forward to finding out once and for all which weighting this lens is!

Will shoot it out and post, as soon as I get my M-mount ring back (left it at my flat 150 miles away!) Apparently there were only 20 of the iscorama 1.33x version made worldwide, it is a truly rare piece. Only time will tell. I'm now kind of hoping it will be confirmed as 1.33, although I don't really mind, this will mean I can get closer to 2.39:1 - fantastic!

Will post back with results soon. :)
 
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Nick Walters said:
Make sure your output/export/whatever is set to square pixels 1280x480(if exporting for inet), and your end result should be fine
Click to expand...

Hi Nick,

Maybe that would work in other NLEs but In Vegas, setting square pixels and exporting as 1280x480 will result in image cropping (it just changes the frame, not the image ratio). In Vegas, I think you have to make project properties 1280x480 and also set the PAR to 1.5 (i.e. not square).

Do correct me if I'm wrong or misunderstood your post! :)

Matt
 
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I've been meaning to shoot a similar test - could you share your test chart when you finish it, as a jpeg or pdf file? My first effort didnt turn out right - I'm not very good at adobe Illustrator and I have to start over. My circle got squished and locked to the main layer... whoops.

I suspect many people are having a difficult time sizing anamorphic images to a NLE. One thing that throws people off is that these ISCORAMA lenses seem to distort faces in close-up. They are built for middle distances, and are like all lenses a compromise at the extremes. Judging an unsqueezed picture by eye is a joke.... we've all seen too many music videos and television broadcasts of 'scope movie credit sequences, and sports broadcasts in bars.... etc, and our brains are scrambled. Hard to tell what is "right" anymore.

It would be cool if you really have a 1.33 iscorama. WOuld it have been so hard for these people to engrave the lens barrel?
 
Jean Dodge said:
It would be cool if you really have a 1.33 iscorama. WOuld it have been so hard for these people to engrave the lens barrel?
Click to expand...

Tell me about it! :)

Yes, I'll post up my chart soon. It's easy to make, you can use any basic program, even 'paint' on windows will do it; just draw a circle using the circle tool. Then select 'stretch horizontally', and put in 150%. Do another circle stretched at 133%. You can do this with any symmetrical shape.. Make sure you label each image so that you know which is which when you film it!

I'll post up my chart and also my results when my mount adapter is returned to me. Why is it when you're excited about something it takes so long to happen?!

Matt
 
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matt9b said:
Hi Nick,

Maybe that would work in other NLEs but In Vegas, setting square pixels and exporting as 1280x480 will result in image cropping (it just changes the frame, not the image ratio). In Vegas, I think you have to make project properties 1280x480 and also set the PAR to 1.5 (i.e. not square).

Do correct me if I'm wrong or misunderstood your post! :)

Matt
Click to expand...

Woow, I didn't know this...I guess I get so used to using all my Adobe stuffs that I forget that it may be different for everyone using something else.

From the sound of it, I'd end up pulling out my hair trying to figure out the export settings on anything else, lol.
 
Math is not the key to unsqueezing anamorphic - YOu need to shoot charts and resize according to the standard of making a circle and/or a square return to proper shape at the given focal length and subject distance. DOn't be surprised if the values change somewhat from A lens to A lens and even from close to far.


and yeah your test is password protected
 
Hey, that's pretty cool.... where did you read that they only made a handful of these? I wonder if they are all iscorama 36's? Your 16:9 sensor is making an image that will be 1:2.36 ratio when it is un-squeezed. Sweet.

What is the size of the front element and the filter threading on the Isco 36? ( The 54 has a 72mm front filter thread size.) You need to get an 0.5x close up diopter. And a rental contract ready for all the people who want to borrow this lens.

I'm still not sure that these Isco anamorphic lenses aren't compressing the horizontal at one ratio, but creating barrel distortion that can and probably should be dealt with on a sliding scale depending on proximity to the focal plane. The distortion is clearly more noticeable at close ranges and on faces, but that's more psychology than optics...
 
Jean Dodge said:
Hey, that's pretty cool.... where did you read that they only made a handful of these? I wonder if they are all iscorama 36's? Your 16:9 sensor is making an image that will be 1:2.36 ratio when it is un-squeezed. Sweet.

What is the size of the front element and the filter threading on the Isco 36? ( The 54 has a 72mm front filter thread size.) You need to get an 0.5x close up diopter. And a rental contract ready for all the people who want to borrow this lens.
Click to expand...

I read it online on a lens fanatic's website who apparently used to work for iscorama. A friend of mine who is a geek for old lenses, told me there were 20 made.

Even though this one is solid and well looked after, I want to keep it that way so I wont be renting it out lol! I'm actually worried about something happening to it every time I turn the focus.. I've had many old lenses where the focus ring gets damaged over time. This one is in excellent condition, but I don't know what I'd do if this broke as I doubt there is anyone who can repair it.

I have my 0.5 achromat diopter on the way. :)

I'm surprised you say the isco 54 has a thread of 72mm. I believe it is 95mm. Here are some specs of some iscorama lenses:

ISCORAMA-54
Magnification (horizontal).......1.5x
Distance Scale..........2m to infinity
Rear Barrel Diameter...........78mm
Rear Lens Element Diameter...54mm
Length..............................102.5mm (maximum)
Net Weight........................1000 grams
Filter Thread......................95mm
Rear Barrel Threading.........77mm
Light-loss Absorbtion...........1/3 Stop or less

ISCORAMA-42
Magnification (horizontal).......1.5x
Distance Scale...............2m to infinity
Front outside diameter..........87mm
Rear Barrel Diameter.............43mm(?)
Rear Lens Element Diameter...42mm
Length..............................83mm (maximum)
Net Weight........................750 grams
Filter Thread......................82mm
Rear Barrel Threading.........62mm
Light-loss Absorbtion...........1/3 Stop or less

ISCORAMA-36
Magnification (horizontal).......1.5x
Distance Scale...............2m to infinity
Front outside diameter..........76.2mm
Rear Barrel Diameter.............52mm(?)
Rear Lens Element Diameter...36mm
Length..............................73.9mm (maximum)
Net Weight........................400 grams
Filter Thread......................72mm
Rear Barrel Threading.........49mm
Light-loss Absorbtion...........1/3 Stop or less

ISCORAMA WIDESCREEN 2000
Magnification (horizontal).......1.5x
Distance Scale...............none (fixed focus range 6m-inf)
Front outside diameter..........59mm
Rear Barrel Diameter.............49mm
Rear Lens Element Diameter...36mm
Length..............................50mm (maximum)
Net Weight........................225 grams
Filter Thread......................none
Rear Barrel Threading.........49mm(?)
Light-loss Absorbtion...........1/3 Stop or less


My iscorama 36 has a front thread of 72m. It is a 2 piece unit, and the whole thing works as a 50mm anamorphic lens for a camera. It has a fast 50mm lens on the back, with an anamorphot on the front that can be disconnected and reconnected. The 50mm lens on the back, was designed for use with the front anamorphot; however, I believe you can swap the lens on the back with any lens, if you wish (I doubt I will do this as I'm lucky to have the original lens designed for it).

The guy I got this from didn't know much if anything about iscorama's, and it was the only one he had - in its box and hasn't really been used. I already knew I was lucky to find one, but now think this was a real find.

PS- I think I just found some more info on it: "One of the most unusual (and rare) lenses ever produced for the Exakta was the Isco Göttingen 50mm f2.8 Iscorama. During photo taking, the lens permits vertical or horizontal picture shrinkage. It's a two part lens, a modified automatic 50mm f2.8 and a special anamorphoser." - this is what I have I think.
 
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I made a mistake when i said the iscorama 54 had a 72mm front - i was tired and meant to say the icorama 42 had a 72mm front thread. I don't know about the 54 model.... I have a 42 but i do notice that list you pasted has some errors.... including the aforementioned 72mm thing - it looks like a typo. The front thread is 72mm and the rear is 52mm which works great with nikkors.

My iscorama also came with the built in 50mm rear or "A" lens attached but it does not clear my canon 5D mk2's mirror. It is also not as fast or as sharp as the lenses I use with it - manual focus nikkors - 50mm f 1.8, 85mm f 1.8, 105mm f2.0, 135mm f 3.5 and a cheap push pull zoom, nikkor 80-200mm.

You should give some thought to setting that rear lens aside for some better glass.... so you can have a wide, a normal, a close up and a telephoto to shoot with.
 
Jean Dodge said:
You should give some thought to setting that rear lens aside for some better glass.... so you can have a wide, a normal, a close up and a telephoto to shoot with.
Click to expand...

The back of the anamorphot sticks out really far in the centre; I don't know how I would fit another brand of lens behind it, other than the iscorama one it was designed for.. which has its own built in 'hole' where the anamorphot's big 'arse goes..
 
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