Nikon DX Lenses on Epic?

[Nate Smith]

Does anyone know if Nikon DX lenses will vignette on EPIC? They've worked great for us thus far on the red one, but we're looking to build out our kit and don't want to shoot ourselves in the foot for when we get our EPIC...

Would it be a better idea to get Nikon FX lenses, or perhaps used pre-digital film lenses?

Also, any suggestions as to good lenses to look out for would be appreciated. Have heard for instance the zooms that have a constant F stop, rather than a floating range, perform better. True?


(We're really only looking at Nikon since budget is a factor, and they seem to be the best bang for the buck)

Cheers,
Nate

[D Fuller]

It's a bit risky to invest in DX lenses for 5K. I would not do it without some testing.

Matthew Duclos, in his Lens Image Circle Database (http://web.me.com/ducloslenses/DataRef/ImgCir.html) lists the diameter of the image circle required to cover a Nikon DX frame as 23.6mm. A Red S35 frame is listed at 33.54mm, but that is the full size of the MX sensor. It appears that 5K will require a ±31mm image circle if the lens is not to vignette.

So to accept on faith that a DX lens will work for 5K on an Epic seems risky. The 5K frame needs 6-7 extra mm.

You can test by shooting the lens on a Nikon FX camera and doing some calculations on the images. (If you're a good prospect, a photo store should have no problem letting you do that.) I'm in the process of replacing several DX lenses I own with FX lenses. The Duclos 11-16 will work, according to Matt Duclos's chart, but I don't know about the Nikon 17-55 or the lovely 10mm DX fisheye. I'm really hoping that one does work.

As for zooms with a constant f-stop. It's not that they "perform better" it's that you need them if you want to actually zoom within a shot. With a zoom that varies its aperture as you zoom, you'll change exposure as you zoom. So you can use the lens as a variable prime, adjusting the iris for whatever focal length you choose, but you can't really use them as a zoom.

[Nate Smith]

Hey David, thanks a lot... super helpful post!

I sure hope the 10mm DX works on epic as well, it shoots pretty nicely.

[Stuart English]

Obviously depends on the resolution you are going to shoot.

If it works for RED ONE it will work for the same resolution on EPIC.

But 5K may be too much.

[Vance Colvig]

For less than one half the price of the Nikon 10mm is the Rokinon 8mm F3.5 Ultra Wide Aspherical lens that has some very good reviews and looks pretty good on my R1MX. Covers S35mm too.

[Nate Smith]

Hmm wait a sec... with the current Nikon mount for the red (with the manual thumbscrew that adjusts iris) would that not force the lens to maintain a constant aperture, or are there some other mechanics inside the lens that change with the zoom as well?

[Matthew Duclos]

Hmm wait a sec... with the current Nikon mount for the red (with the manual thumbscrew that adjusts iris) would that not force the lens to maintain a constant aperture, or are there some other mechanics inside the lens that change with the zoom as well?

If the lens "ramps" (closes down the maximum aperture towards telephoto) then there is nothing you can do about it. The manual mount you are talking about only presses against the small lever that interfaces with the camera. The aperture in 'G' lenses (the lenses with no aperture ring) is spring loaded to close automatically. The small thumb screw pushes up against the lever that opens the spring loaded iris and forces it open. If the maximum aperture at wide is f/4.5 and the maximum aperture at tele is f/5.6, and you set it to 'wide open' at wide, as you zoom to tele the aperture will close slightly and you WILL lose the light. I hope this makes sense.

[OptiTek]

Hmm wait a sec... with the current Nikon mount for the red (with the manual thumbscrew that adjusts iris) would that not force the lens to maintain a constant aperture, or are there some other mechanics inside the lens that change with the zoom as well?
The variable aperture on still lenses is an optical design compromise and has nothing to do with mechanical packaging.
F-stop is simply a ratio between the pupil size and FL. For very long FL the pupil size would have to be really large to keep the low ratio(i.e F-stop)
That would result in huge glass elements and great expense as well as weight, size, portability disadvantage. Therefore the designers decided to keep the design "practical" and "forced" the F-stop(pupil size:FL ratio) to increase as the FL increases.
pretty simple, really...

[Stephen Strangways]

Exact coverage varies greatly between specific lenses. For example, Tokina's 11-16mm is intended to only cover APS-C (aka DX in Nikon-speak) but if you remove the hood, it will cover FF35 (aka FX) from 15-16mm, albeit with somewhat soft corners wide-open.

The only way to know which Nikon DX lenses will work on EPIC 5K is to test each and every different lens. Just remember you could always fall back on 4K for the lenses which vignette on 5K.

[Nate Smith]

ah, that totally makes sense. thanks guys!