For Historical technical Interest - Groundlgass Adaptors.

[Ken Willinger]

Man i used to have a set of Canon FD primes to die for. Hand picked over the course of 10 years. ( iused to shoot stills on a AE1 program)
Sold them all to buy a stupid fucking 5DmkII. Worst money i ever spent, as soon as the 5DmkII was in the mix, i spent 5,000 in accesories to make it work, and NOONE wanted to pay for it as a rental. I lost 8500 on that camera.

That was a nice set. I've got a similar set and had some of them cinevised including the
20mm 2.8
35mm 2.0
55mm 1.2
85mm 1.8

I have a bunch more that are not cinevised but are terrific looking with the Epic including some non Canon FD glass
Vivitar 28mm 2.0 close focus
Kiron 105mm 2.8 macro

Sorry to hear about the 5D fiasco. I held out and never bought into it until recently (5DMKIII) for a specific job. I use it mostly for stills though.
Love the FD glass with the Epic!

 

[Mitch Gross]

I thought it increased the relative aperture size and decreased the dof as it relayed down the areal image that normally is projected on the ground surface?

The only way to replicate the depth of field effect is to rephotograph it. Otherwise everyone would have just used a series of glass elements rather than rephotographing surface images.

 

[Wayne Morellini]

The only way to replicate the depth of field effect is to rephotograph it. Otherwise everyone would have just used a series of glass elements rather than rephotographing surface images.

You are positive Mitch, It probably wouldn't even had occurred to people that it could be different. Once they see something they follow like a sheep herd of lemmings. I know one of the adaptors is telecentric relaying perfectly parallel rays at the target like a perfect ground glass setup would, big thing from memory. But I thought a relay could get the defocused parts and relay it down to the sensor decreasing minimum dof. Did anybody actually look into this? I was aiming for very low light SBD compactness but did want to preserve some shallow dof for affect (I d:fn't really need to have the depth of a number of dimples on an orange only in focus).

I can't remember exactly what I found looking into it, the threads themselves where pretty light on explanation, and I dropped it early to go for the cinema cameras.

 

[Wayne Morellini]

But there are more modern solutions I have on my books to look into, one, a flat lens design, has a similar issue to resolve in retaining the 70mm format dof down to small formats, but luckily I don't have to use that. Now post focus is possible you could setup a simple lens array post process dof etc and call it not IMax.

 

[Mitch Gross]

I could take make old Jeep Wagoneer and make it go 100 mph or use a Ferrari to pick up groceries, but neither is a particularly effective use of resources. ;-)

To answer the question, yes, I am sure. This is a fundamental factor in optical design. Otherwise no one would have bother with these messy spinning disc rigs.

 

[Wayne Morellini]

Thanks for the verification Mitch, sorry to question it, as most people say these things on folk lore and in the end if you believe them you find out they don't usually know, so I had to check. I thought I found a different answer back then, but I had dropped interest in it and didn't pursue it. I was actually interested in telocentric lens design until I got diverted to this. But as for most of those guys they didn't do much research past projection surfaces. A lot of fly by the pants and very little research past asking or copying somebody else in the early days before I moved on. At least it would have eventually gone to research as they became commercial products. We see it all the time, nothing can be done better, otherwise everybody would do it, and generally wrong. People could have said that only hollow lens mounts work as converters otherwise everybody would be doing it. Just human nature and the. bane of every inventors existence.

Thanks again Mitch