Relay lens for 1/2" AND 2/3" sensors (for Dof adapters)

[dadoboy]

Yes, thanks for punching in the numbers correctly cordvision (forgot your real name). If you don't trust me ( and you should, I'm a nice guy ), then trust these calculators. For the same focal length/t-stop/distance, on different formats, the smaller the circle of confusion, the LESS depth of field.

Not a lot of people know this, so we can be proud . Now if it can only me get more DP gigs somehow. Anybody need a shooter with a Palm Pilot? Sorry, no camera included unless you want to shoot film!

 

[Marshallarts]

Oh... well yeah, I guess I did misread that. But I would never mean to confuse 85mm in 35 with 85mm in 16. Two completely different focal length!

"Ahhhh!", you say? But please.....(shaking head). My entire argument (unless I really miswrote something here) was in using 16mm vs 35. Why oh WHY would I intentionally be using completely different focal lengths when trying to compose the same shot on different formats? This is exactly what has been frustrating me. Everyone keeps going back to FoV and I don't know why?

All I'm saying is, if I use a 16mm camera and a 35mm camera, and shot the exact same shots, the 35mm will be a shallower DoF.

I'm really talking basic practise here. Bringing your technical jargon into this really throws me off. If I were to take a picture of you with an APS camera and with a FF35, the FF35 will have a shallower DoF. Why in God's name are we discussing my using the same focal length on both cameras? It's not the same shot. I NEVER meant this to be part of the discussion.

 

[cordvision]

Oh... well yeah, I guess I did misread that. But I would never mean to confuse 85mm in 35 with 85mm in 16. Two completely different focal length!

That is the big misconception here. A 85mm lens is a 85mm is a 85mm lens. It doesn't matter with what camera you use it! This is something that gets so often miss quoted and is the reason for a lot of confusion. Even big camera manufactures are guilty of that when they advertise their small format cameras. The thing that changes is the FOV, the focal length of a lens stays always the same. It is very important to distinguish between FOV and Focal Length...

"Ahhhh!", you say? But please.....(shaking head). My entire argument (unless I really miswrote something here) was in using 16mm vs 35. Why oh WHY would I intentionally be using completely different focal lengths when trying to compose the same shot on different formats? This is exactly what has been frustrating me. Everyone keeps going back to FoV and I don't know why?

You actually would use different focal lengths when trying to compose the same shot on a 16mm camera vs a 35mm camera!

All I'm saying is, if I use a 16mm camera and a 35mm camera, and shot the exact same shots, the 35mm will be a shallower DoF.

Agree...

 

[dadoboy]

Sorry if I did not make that clear Marshall. I was speaking purely in terms of DOF and focal length and format. FOV adds another dimension, and it is one of the things that makes 35mm movie making more special than 16mm (and why we are in this forum), because ultimately the shots you get on 35mm will use longer lenses, and those lens choices for FOV will afford a shallow and special DOF.

 

[cordvision]

Not a lot of people know this, so we can be proud . Now if it can only me get more DP gigs somehow. Anybody need a shooter with a Palm Pilot? Sorry, no camera included unless you want to shoot film!

We are working on a short we might shoot on film (still punching the numbers, budget is tight).

Even tough it got a little bit heated in this thread, I enjoyed the discussion. It made me look deeper into certain aspects and I definitely got something out of it

 

[dadoboy]

Cool. Message me if you need a DP. You seem very technical yourself though, probably up to the job. I was half joking. I own some Arri's. But I shoot on everything. Do you know Giacun Caduff? He's a filmmaker from Switzerland, really great guy (yeah, it's a big country I know).

 

[Marshallarts]

You actually would use different focal lengths when trying to compose the same shot on a 16mm camera vs a 35mm camera!

Please..... I can't take this anymore. I know this. I've ALWAYS known this. That's what I meant. After all the technical stuff I've provided please don't think I don't understand this.

All I'm saying.. All I was EVER saying.. Is that in choosing a 16 vs a 35 system, you get a shallower DoF in 35.

Then everyone started debating and talking about FoV. All I'm saying, is 35 has a shallower DoF. That is after all why we want a 35mm DoF adapter to get a shallower DoF with the smaller sensor cameras.

Can we finally agree on this? Is there something I said you don't agree with? If you guys know these principles, and I know these principles, then what the heck are we arguing about?

"In practise" 35 has a shallower DoF than 16... That's all I ever said. Is that really a difficult issue to discuss? It's so obvious to me I have no idea why we started getting so technical.

But you can understand why I was getting frustrated right?

By the way, I'm a focus puller too. And a DP, and a photographer. Geesh. This is such simple stuff! Did I really say something wrong by accident earlier than threw me off the past 30 posts?!!??

 

[Lenilenapi]

Marshallarts,
I couldn't get through half of all this but I was happy to see you mention the importance of "Circle of Confusion" as an important variable in all this. Because the target circles of confusion for being "in focus" actually differ depending on the medium and how much it may be blown up, I'm actually a little skeptical about using DOF tables designed for 35mm in video. 35 and 16mm have different CoC's in the American Cinematographers manual and I think that's an entirely different issue than FOV. God knows how to figure it out for video.

As a focus puller you'll be very sensitive to this. The thing to do would be test those tables before assuming they are gospel in this medium.

Lenny Levy

 

[Easom Aerospace]

Price vs. performance

Price vs. performance

OK I'm jumping in...

The best design (or the better performing) is the one that its for a limited uses in a very specific target and not able to do everything...

This is one of the best posts I've ever seen. So true it is. I've learned something about the prosumer. Only about 3% of the people want an adapter to perform as it should on a certain camera. 97% of the people would rather have a unit perform almost as it should, but work on every camera. So from a marketing standpoint, it is much better to make a unity that performs well on all cameras but does not perform to it's peak. Ther peak performing units that work perfectly on a certain camera, you keep for yourself and use them.

My guess is that the end result of Cinevates relay will be a unit that will perform very well on all cameras of that mount. That's what the people prefer. A low price point, with the sacrifice of perfection.


I'm really liking the Panavision Genesis! lol :cheesy:

Cory

 

[Marshallarts]

(on technical hurdles during R&D of Cinevate's new multi-format Relay) 3. Achieve an f/stop rating that would rival the typical stock B4 lenses....but be sharper wide open, and of course be packaged as compact as possible.

Can someone please explain to me the use of the f/stop in a relay (or DoF adapter for that case)? DoF is achieved through the lens which comes after either adapter so I unsure of the benefit with it before the lens (other than to simply lower light levels). I.E. I used a Nikon Relay a few month back (w/out the adapter) so we could adapt a 15mm Nikon still prime on the F900. The Nikon Relay has a f/stop ring on it. This is what I'm referring to. Please let me know if what you meant is that this relay can handle a wide range of f/stops on the lens after the adapter where typically it would vignette. That I understand.

there are B4 2/3 to B4 1/2 adapters in the market... I don't know how they will perform in such a combination...\

Having not heard of this adapter I did some digging and all I found was this Fujinon at B&H but it still cost ~$2500. Is this what you're referring to? Seems pretty expensive (halfway to buying a dedicated relay!). Also this is 1/2" >to> 2/3", but you mention 2/3" >to> 1/2". Are there both?

If I were to choose one relay with the intention of using it on multiple systems, I'm wondering what people would say is the best route (in preserving image quality). I know the best would really be get the one for whichever camera system you intend on using it the most. But thought maybe there would be an expert opinion on this.

 

[Dennis Wood]

M, the relay lens has light loss like every other lens, so this does play into how efficient the system it is. Having an f1.4 lens would have been possible, however if it's not sharp wide open, who cares how fast it is? Our goal was to ensure the lens met specs when used wide open, but still offered exposure control. So the aperture on the relay will be your prime method of controlling exposure to the CCD/CMOS array. The aperture on the taking lens out front does control exposure, but not in the way you'd predict. The best of explaining this would be check our clip on Cinevate's Video University: "Brevis35 - Light Loss - More efficient than you’d think!"

Our multi-format relay is the only one in the world capable of supporting both SLR lenses and Cine lenses out front with zero crop factor...so in this regard we figure it makes for some serious value whether you're shootin with an SI 2k camera or an HPX500