Mini35 + 35mm SLR primes good enough for HD?
 

I know still 35mm primes have been used with great success with the mini35 and the XL1/XL2. But would the primes be good enough when shooting HD with a HD100? I know of the focus pulling shortcomings of still primes, but would the quality be on pair with 720p? Or would it be better to get a cine zoom? I'm sure I can't afford cine primes.
Also, between the still primes, are the Zeiss really that much better than the Nikons? And do the Zeiss come in a different mount besides M42?
Thanks.

just an idea, the slr lenses are at least meant to be used for shooting high resolution chemical photos. i cant see a reason why a lense made for something like that wouldnt be good enough to be used for hd digital photos

Still lenses should certainly be able to resolve 720p resolution, in fact beyond that. Quality still lenses such as Nikkors are optically on a par with cine lenses, again certainly as far as the limitations of this medium are concerned. The standard mount for the Zeiss lenses is PL; you can find older Zeiss lenses with the "B" mount also.

Still primes are not always lesser....
 

Michael - you might also consider that the 35mm primes are designed to have a larger image circle - as they were intended for a slightly larger inage area than 35mm cine film. This is a GOOD thing - because they vignette a little less - many PL mount lenses tend to fall off a little at the edges [you often see it in people's "I shot it with Zeiss superspeeds" clips - and that can look great in a filmclip, although it's not to everyone's taste.

Anyway -- you can snag a good set of Still primes online with a bit of persistence - and for MUCH less than 1.3 superspeeds.

So they aren't a second rate option in all cases - if you want to finesse every detail [this is for an image converter after all] - then shoot on HD with the Pro 35 converter.....or on film.... :-)

This of course begs the question: why would anyone use cine primes instead of still lenses, if they cost so much more?

Still lenses may have a tendency to breathe, i.e. appear to magnify when one racks through the focus from close to infinity. This phenomenon isn't an issue for still photography, but obviously is for motion work (and can be seen with inexpensive video zooms). In addition, still lenses will almost certainly have a shorter throw to the travel of the focusing ring, which will make it trickier to set marks as they will be so close together. If one intends to pull focus oneself rather than use a camera assistant, this may not be a problem.

John, I have yet to have experienced edge vignetting on the projects I have shot with the Mini and Zeiss speeds, even when projected or on the web (i.e. full frame video). Consider that the size of the Mini35 frame is not greater than the Academy 35mm aperture for which the lenses where designed; obviously they would not have passed muster if they vignetted when used for motion picture work, where such an issue would have been very noticeable when projected. Perhaps the vignetting you may have seen was caused by other factors?

For almost 2 months I didn't have a single reply for my question and I had completely forgot about the thread. As they say, better late than never :)
In the mean time, I learned about Lomo cine primes, which are quite affordable. I was really thinking about going that way. But then somebody told me the Lomo lenses were not that good and that I would be better off with Nikkors in terms of resolution and overall glass quality. So I'm not really sure now. The Nikkors are cheaper (although really not that much cheaper than Lomo cine primes sometimes), but has the focus breathing and tracking issues. Lomos are more expensive, but are real cine lenses. The quality between the two is the blurred point. Anybody knows?

Hey Michael,
I can't speak for the Lomo's, but I've got a full set of Nikkors that I've used with a mini35, and they work great; however, Charles' points are well worth noting, particularly the breathing and the short throw in the focus. I think you can deal with them pretty well, though the breathing can get annoying and it's funny because it really differs lens to lens (wrt to focal length, not indiv lenses). But, I don't see how you can get a full set of Lomo primes of the same speed as the faster Nikkors for the same money. There's so many Nikkors out there that you can get some great deals.

As far as resolution, the 35mm still primes are being used quite successfully on plenty of digital SLR's with tons more pixels than HD. I think HD is only about 2 MP resolution.

You are right. Lomos will be more expensive. The normal speed ones (F2.0), are not so much more. But the high speed Lomos (F1.5), are quite high in comparison to Nikkors. In my opinion, the F2.0 could do quite nicely though. I don’t think you really need the high speeds.
Unfortunately, breathing is a bad thing with the still primes.

But....

HDCAM as 5micron pixels neding about 100lp/mm resolution,
a Canon 20D has 6.4micron pixels needing about 77lp/mm resolution,
Canon 5D has 8.2micron pixels 61lp/mm,

hence a lens that's sharp enough for a high-end D-SLR is not sharp enough for HDCAM, and not sharp enough by a factor of 2 again for a 1/3" HD camera, which needs in the region of 150 to 200 lp/mm resolution because of the very small size of it's pixels.

Graeme

Some things to consider:

You are already losing between 1.5-2 stops within the Mini35, so there is an obvious advantage to having the fastest lenses in front as possible to give you some flex. Shooting interiors or night exteriors with the setup means using larger and more lighting instruments than you would with a straight DV setup. The difference between a f1.4 and an f2 lens is exactly half as much light transmission, meaning a 300 watt light must be replaced by a 600w, and so on up the line.

Remember also that many lenses are not at their optimized performance wide open; with a slower lens you will likely find yourself shooting this way more often. Plus, the primary reason for putting onself through the expense and complication of the Mini35 is to achieve shallow focus, and that extra stop will make a noticeable difference to that end.

This all said, the lenses you describe are perfectly workable and I have shot a few Mini35 projects with standard speed Zeiss lenses for budgetary reasons.

If you go by that, not even cine lenses would be sharp enough for HD. But cine lenses are used all the time for HD with great results.

HD supposedly already calls for more light. But in tests I did, it didn’t really seem that bad.

Interesting. I did some sensitivity tests with the HD100 using the same light set up I used to use for ½” DVCPRO and DVCAM cameras. I could get away with the same F4-f5.6 exposure I shot with the bigger ½” cameras, using exactly the same lights, when shooting with the HD100.
So, if when using a 500W for key, I can have the stock lens on F4, how much more light will I need to get the same exposure when using the Mini35?

The Panavision HD lenses are a lot sharper than their 35mm ones, and it shows. They were not happy with the performance of 35mm lenses, so they developed their HD ones....

At least, that's what John Galt told me....

Graeme

Graeme is correct. The mandate went out to the lens department at Panavision that they needed to develop lenses with twice the resolving power as the existing Primos, and that would be optimized to work wide open (even the zooms). Now that the Genesis is functional and has a 35mm sized sensor, this is no longer an issue; we are hoping that Panavision will apply the new techniques they developed for the 2/3" lenses and bring out a new set of 35mm and Genesis compatible primes and zooms.

Michael, I'm afraid I don't have the exact conversion figures at my fingertips--only having a brief time with the HD100 and Mini35, this was a factor that I wish I had remembered to note. I seem to remember that a 4 on the stock lens corresponded to the Mini35 with a prime at T1.4 and the relay wide open, but this would indicate a 3-stop loss and that seems extreme.

It seems to me that the following statement is incorrect when a mini35-type adaptor is in use.

This would be true if the lens was projecting an image directly on the relatively-small CCD sensor -- but it's not. It's projecting onto a 35mm-size patch of ground glass, which is then photographed at a resolution significantly less than the film for which the lens was designed.


BW