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-   -   F3 sensitivity against EX1 (https://www.dvinfo.net/forum/sony-xdcam-pmw-f3-cinealta/498550-f3-sensitivity-against-ex1.html)

Michael Power July 18th, 2011 07:40 AM

F3 sensitivity against EX1
 
Looking at a range of still lens for my F3 and wondering if its increased sensitivity over my EX1 is measurable in the number of stops? I've been shooting a whole bunch of talks in halls using existing lighting where my EX1 is set around F2. If I use the F3 with a lens with max aperture of F4.5 will I have enough light? Will I go far into gain? Thx

Chris Medico July 18th, 2011 09:11 AM

Re: F3 sensitivity against EX1
 
The F3 is a lot more sensitive than the EX1. You can run a lot more gain on the F3 and get a completely usable picture where I've found with my EX1 that +3 is the limit before there is too much noise. The F3 at +18 looks cleaner than the EX1 at +3. Also the noise you get on the F3 is not as objectionable as the noise on the EX1. I don't have actual numbers but its got to be in the area of 3 stops faster when you take into account the usable gain range of the F3 in comparison to the EX1.

I've been planning to make a demo reel to show clients the advantages of stepping up to the F3 on their shoots. Showing light sensitivity advantages of the F3 over the EX1 is one of the comparisons that will be included. It won't be a scientific test but real world examples.

Thierry Humeau July 19th, 2011 08:32 AM

Re: F3 sensitivity against EX1
 
Michael,

The F3 is indeed more sensitive but using F4.5 lenses, you will end up defeating one of the main aspect of large sensor cameras which is to obtain a shallow depth of field and soften the background.

Best,

Thierry.

Dave Sperling July 19th, 2011 02:14 PM

Re: F3 sensitivity against EX1
 
A bunch of different variables involved...
Though I've found the F3 a little faster than the EX1, I think that's particularly true at 1080i.
With the settings I've been using to more or less match my F3 and EX1 when shooting on a recent project (1080p30 / Cine 3 gamma) I've found I get about the same exposure level from the EX1 wide open that I get on the F3 from a Nikon 80-200 / 2.8 wide open. Both set at 0db gain. Admittedly the Nikon probably loses some light internally (the 2.8 is an f/stop, not a t/spop) so I'm guessing the F3 is just over a stop faster than the EX1.
That doesn't get you to a 4.5 as a comparison stop, so I'm thinking you'll be aroud +6 or +9 db on the F3 for matching exposure level. However, the F3 still looks great at those increased db levels.
But I would still recommend getting a faster lens if you can...
NOTE: The findings above were completely unscientific, they just happened to be the exposures I picked in working to get matching shots on the two cameras with my picture profile settings in place.

Alister Chapman July 19th, 2011 02:25 PM

Re: F3 sensitivity against EX1
 
At 1080i the F3 is 800asa, the EX1 approx 360asa, so about one stop between them. But it's the noise that makes the difference, or in the F3's case the lack of it.

This means you can use +6db and gain another stop or even +12db gaining 2 stops and making the F3 3200asa yet still have a useable image. At +6db it's still cleaner than the EX1.

Michael Power July 19th, 2011 07:03 PM

Re: F3 sensitivity against EX1
 
Thanks for info. That's about what I was expecting and hoping for, one stop extra at 0db, then two stops more with negligible gain.

Thierry, I have some primes and a couple of shorter zooms which are all about 2.8 which are fine for stop-start shooting, but there are situations when stopping for a lens change is unfeasible and a short DOV is not the best approach. Pragmatically, I need a zoom lens that will emulate the EX1's lens for talks and fast doco shooting.

Any suggestions in the Nikon-mount stills domain?

Thierry Humeau July 19th, 2011 09:01 PM

Re: F3 sensitivity against EX1
 
Michael,

In my quest for great Nikon mount zoom lenses for the F3, I came to realize that the best candidates as far as price/performance, are actually not from Nikon. Here are a few suggestions:

- Sigma 18-50 F2.8. It has been discountinued and replaced with the 17-50 F2.8. I like the older model because it does not have IS (Image Stabilization) which the MTF mount cannot utilize anyway and because of this, the lens is lighter, simpler and minimal focusing distance is better than the the new 17-50. Also, the focus ring has a bit better range, not great though.

- Sigma 50-150 F2.8. This is a fantastic range for interviews if you need to vary betweeen two frame sizes. That lens has also been discountinued by Sigma but can be found on eBay at around $650. It is pretty much the equivalent of a 70-200 on a full frame SLR. This is quite a unique offering from Sigma as there are no similar offering from other manufacturers with a fast F2.8 constant aperture. Rumors are that they Sigma is about to re-issue a version of this lens with IS.

- Tokina 11-16 F2.8, a great super wide zoom. I am not too crazy about the sliding focus ring to switch between AF and Manual but the built and optical quality are excellent.

The MTF Nikon adaptor is working fine with those lenses but it would be nice to see an adaptor with a larger and smoother aperture control and a way to power the internal IS feature now offered by many of those lenses from the F3 mount.

Any other lenses recommendations are welcomed.

Cheers,

Thierry.

Alister Chapman July 20th, 2011 01:53 AM

Re: F3 sensitivity against EX1
 
For a cheap and cheerful lens, I use the Nikon 18-135mm. It's f3.5 to f5.6, but doesn't really stop down until you go beyond 100mm. The zoom range is very useful and I used this lens a lot at the weekend shooting and airshow. It really is not the best of lenses, telescoping a lot, no calibrated focus scale and not fast. But for run and gun, not having to swap lenses is a boon. It's also surprisingly sharp even wide open and at f4 you still get nice DoF.

Best bit is it's so cheap you can afford to have one just for occasional use. I paid 150 used for mine. Of course once I get my 2/3" B4 adapter into production all these issues go away :-)

Ned Soltz July 20th, 2011 08:45 AM

Re: F3 sensitivity against EX1
 
While the thread has already gone somewhat OT, question about those Sigma lenses-- Are they internal focus/non-telescoping for mattebox purposes and are they parfocal?

These are of course the basis for the Red 17-50 (18-50) and 50-150 rehoused glass.

Ned Soltz

Thierry Humeau July 20th, 2011 10:05 AM

Re: F3 sensitivity against EX1
 
Ned,

I am away from the office now but all these lenses are internal focus, I think the 17-50 (18-50) expands but neither the 50-150 nor the Tokina 11-16 do.

T.

Alister Chapman July 20th, 2011 02:26 PM

Re: F3 sensitivity against EX1
 
The telescoping issue is why I keep coming back to my old Tokina AT-X Pro 28-70mm f2.6 Mk1 lenses. These do not telescope and are of all metal construction with manual focus scale and iris scale. Optically these are good lenses provided you close down by a half stop, so really the useable max aperture is f3.5, but they are constant aperture throughout the range and focus shift is minimal as you zoom.

I wish I could find a non telescoping 20-80mm (or thereabouts) f2.8 zoom that's sharp at f2.8 and constant aperture, manual iris ring, good fixed focus scale.

Warren Kawamoto July 20th, 2011 02:59 PM

Re: F3 sensitivity against EX1
 
Off topic, but does anyone know how visual noise levels compare between the F3 and FS100? I would assume the F3 is much better?

Alister Chapman July 21st, 2011 12:53 AM

Re: F3 sensitivity against EX1
 
To be honest there isn't much difference. Noise levels and visibility are similar.

Timur Civan July 22nd, 2011 02:28 AM

Re: F3 sensitivity against EX1
 
From what i understand, the FS is really only different image quality wise with regards to dynamic range, and even then, its a half stop difference.

I've heard the F3 handles the image slightly better overall. i chalk that up to a more expensive signal processor, or even just a somewhat better implementation.

The FS100 is alot of camera for the money. If you dont need, SDI, and all the gadgetry necessary for high end production, its good for 90% of all shoots. infact, i have a shoot tommorow wherei wish i had a FS in stead of the F3. I just need a smaller camera, but not a DSLR.

Alister Chapman July 22nd, 2011 03:26 AM

Re: F3 sensitivity against EX1
 
There is a full stop difference in dynamic range between the FS100 and F3. In addition the processing isn't as sophisticated and the FS100 has slightly lower horizontal resolution. Detail correction and aperture correction are not done so well on the FS100 and the cinematone gammas are not as nice as the F3's cinegammas. Overall the FS100 lacks the verisimilitude that the F3 has. The bigger annoyance is the course steps and limited adjustment range in the picture profile settings. While you can change most things often the range is just +/- 7 steps.

I don't want to sound too negative about the FS100 as it is a great little camera and not that far from an F3, but the F3's images, for me at least have a nicer look.

Michael Power July 25th, 2011 01:33 AM

Re: F3 sensitivity against EX1
 
Hi Alistair

Returning to question of cheapish zooms, I've been experimenting with a few APS-C or DX of varying length and stop and not having much joy. What about a Nikon 35-200mm 3.5-4.5? If I had enough light to work at f4.5 which is the minimum iris for the 200mm end of the lens and I started at 35mm then zoomed in to 200mm, will I still loose 1 stop of light during the zoom? I've never worked with variable iris zooms before so am in the dark here (pun and all).

My need for an extreme zoom range is to emulate my EX1 which I've been using to shoot the occasional lecture. It's a great camera and much as I would like to keep it as a back up/B camera, economics dictate I sell it. And the money I earn from shooting these simple talks is not enough to warrant lashing out on an Optimo or Red zoom. At the same time, the F3 is ideal for a bunch of other projects.

Thierry Humeau July 25th, 2011 07:44 AM

Re: F3 sensitivity against EX1
 
Michael,

Unfortunetely, until Sony comes out with its own motorized zooms, there is nothing in the SLR lenses world that will give you the range and ease of use of the EX1 built-in optic. Aside from the limited zoom factor and high F-Stop of those APS-C lenses, I really have a hard time finding lenses with proper focus rings and mechanisms. In the age of AF, sadly, the manual focusing capability of newer lenses has became more a survival tool than a critical one. On a side note, I discovered a very interesting piece of glass made by Sigma a few years back but now discontinued, the 50-150mm F2.8 zoom. A very good choice for sitdown interviews when in need of 2 different frame values. It also has a very nice and smooth manual focusing ring.

Take care,

Thierry.

Leonard Levy July 27th, 2011 12:51 AM

Re: F3 sensitivity against EX1
 
Nikon 18-200 is what I use for this purpose. Image quality is still quite good but you are slowed down because its varifocal and the iris changes from 3.5 - 5.6 . Despite limitations it allows me to shoot a very wide range of B roll when I need it.

Alister Chapman July 27th, 2011 02:06 AM

Re: F3 sensitivity against EX1
 
It is correct that if you have a zoom where the iris ramps, if you stop down to the smallest aperture the lens will then remain at that aperture as you zoom.

I wrote up a report on using the F3 run and gun here: PMW-F3, Run “n” Gun, is it worth the effort? | XDCAM-USER.COM

Michael Power August 1st, 2011 10:40 PM

Re: F3 sensitivity against EX1
 
Hi Alistair

I had read your report, thanks for that. To clarify, the amount of light hitting the sensor will decrease going from the widest to the longest zoom length, even set at f5.6 on a f3.5-5.6 lens?

Digressing, I'm very interested in your adapter for mounting 2/3" ENG lenses, although one of the not insignificant factors for going to an F3 from my EX1 plus Letus was to avoid the extra weight of the adapter and second lens. When do you anticipate selling some?

Alister Chapman August 2nd, 2011 03:19 AM

Re: F3 sensitivity against EX1
 
If you set the iris to f5.6 it will remain at f5.6. If you set it to f3.5 it will ramp down to f5.6.

I have some production prices for the adapter now and I'm trying to decide whether to go ahead. I need to make 200 units to make it viable, which requires quite considerable up front investment.

Michael Power August 3rd, 2011 10:01 AM

Re: F3 sensitivity against EX1
 
When you comment that the iris at f5.6 will remain at f5.6 through the zoom range, are you referring to the light that makes it through the lens to the sensor or the physical setting of the ring? On one of the lenses I've tested with that goes from 28mm to 300mm, f3.8-5.6, even at 5.6 the light drops considerably (but the rings stay put) as you zoom in.

Brian Drysdale August 3rd, 2011 11:49 AM

Re: F3 sensitivity against EX1
 
The iris stays at the f stop, but when you increase the focal length on the zoom lens, the diameter of the front element is no longer large enough to give you that stop. It's a compromise that lens designers use to keep lenses compact.

Non ramping zooms are larger than those that ramp, for example this was noticeable when Fujinon brought out non ramping high end versions of their video lenses for shooting drama - the size difference was considerable


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