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View Full Version : My lenses and the 2.3X crop factor



syberfilm
04-23-2012, 09:35 PM
Actual Full Frame Size on top
2.3X Crop factor Rounded Off benath 2.3x crop factor based on Full Frame FOV.

Ivan made a great point.. Compared to a Super 35mm movie frame. The crop factor is about 1.6

So Full Frame Vista Vision "FOV" Field of View 2.3x

Super 35mm FOV 1.6X

1 Full Frame Size
2 2.3x crop Vista Vision FOV
3 1.6x super 35 FOV


Tokina 11-16mm F/2.8
25-37mm F/2.8
17-26mm

Vivitar 13mm F/2.8
30mm F/2.8
21mm

Tokina 17mm F/3.5
39mm F/3.5
27mm

Sigma 20mm F/1.8
46mm F/1.8
32mm

Rokinon 24mm F/1.4
56mm F.1.4
38mm

Vivitar 28mm F/1.9
65mm F/1.9
45mm

Nikon 35mm F.1.4
80mmF/1.4
56mm

Nikon 50mm F/1.8
115mm F/1.8
80mm

Nikon 58mm F/1.2
133mm F/1.2
93mm

Nikon 85mm F/1.4
200mm F/1.4
136mm

Nikon 135mm F/2.0
310mm F/2.0
216mm

Nikon 80-200mm F/2.8
185-460 F/2.8
128-320mm

Zeiss 300mm F/4
700MM F/4
480mm

Now remember the Great Akira Kurasawa used a 500mm lens on interior close up shots in several movies. One being Red beard. This movie has some awesome shots in it.
I know wide angle shots will be an issue on the blackmagic cinema camera. But I hope new lenses will come out and maybe someday BMD will release a micro Four thirds mount.

Paul Flack
04-23-2012, 10:54 PM
When I first read about the Blackmagic Cinema Camera I actually thought that it would have an interchangable mount. Too bad that BMD did not take that opportunity. If they will release a Micro Four Thirds mount that will mean buy another camera.
I hope that at least all of their future cameras will have interchangable mounts.

Right now for the BMCC I am looking at the


Tokina 11-16mm F/2.8

Canon EF 16-35mm F/2,8L II USM

and

Canon EF 24-70mm F/2.8L USM

or

Canon EF 24-105 F/4.0L IS USM

even though it seems like Amazon Germany does not have the 24-70 anymore with the Mark II version around the corner. Which is odd, because there still is a market for MarK I, since the Mark II will cost twice the money.

Nick Royer
04-23-2012, 11:56 PM
Canon EF 16-35mm F/2,8L II USM and Canon EF 24-70mm F/2.8L USM or Canon EF 24-105 F/4.0L IS USM

Paul - I would suggest trying these lenses out in a store if you haven't already - I've found that although they do produce wonderful images they are VERY heavy due to all the glass needed to cover a full frame sensor. Maybe take a look at the EF-S 17-55 f/2.8 if you don't have any FF cameras - I am trading out my virtually new 24-70 because the weight makes it hard to use handheld or on a car mount without lots of rigging.

Nick Royer
04-24-2012, 12:00 AM
I am looking at the following lenses:

Tokina 11-16mm f/2.8

Canon 17-55mm f/2.8

and potentially also:

Rokinon 35mm f/1.4

Rokinon 24mm f/1.4


I've heard great things about the 35mm, but am a little concerned about the quality of the 24mm, as I've heard that it has some weird distortions due to being full frame. Will have to take a better look at that one before July.

Jon Neely
04-24-2012, 12:54 PM
Im thinking nikon 600 F4 with some heavy sticks for wildlife a mile or two away.

Osslund
04-24-2012, 05:00 PM
I'll get that Tokina 11-16 again and use my EF lenses 16-35/24-70/70-200/35/50/100. Should cover everything but an ultra wide scope.

Ivan
04-25-2012, 10:04 PM
Okay,

This 2.3 crop factor business is confusing and not the norm for filmmakers over the past 50 years. Let us remember that the standard has been super 35mm film for a very very long time now which has a horizontal of approx 25mm, *not* the 5Ds massive Full Frame 35mm sensor.

So since this is a digital cinema film making camera I propose that the "crop factor" be measured from this Super 35mm standard, unless it is made clear that you are comparing it to a 5D.

Red, Alexa, 1D, (7D... is close), Arri film cameras, Panavision, all apsc-apsh-super35 etc. They all have pretty much super 35mm sized sensors.

So this would mean the crop factor from super 35mm film to the BMC would be 25/15.6 = 1.6

not 2.3

so this would make the Tokina 11-16 equivalent Field Of View to an 17.5 - 25.5mm on any super 35mm sensor. To be honest with you, that is nice as a wide - I rarely go beyond that. Citizen Kane for example never went beyond a 25mm lens.

I understand that some of you are coming from a background with a 5D, but for the sake of keeping things clear (and not overly confusing the issue) lets state whether the crop factor is in relation to FULL FRAME 5D size, or super 35mm sized fields of view.

That is all :)

Cheers

Ivan


Actual Size on top
2.3X Crop factor Rounded Off benath

Tokina 11-16mm F/2.8
25-37mm F/2.8

Vivitar 13mm F/2.8
30mm F/2.8

Tokina 17mm F/3.5
39mm F/3.5

Sigma 20mm F/1.8
46mm F/1.8

Rokinon 24mm F/1.4
56mm F.1.4

Vivitar 28mm F/1.9
65mm F/1.9

Nikon 35mm F.1.4
80mmF/1.4

Nikon 50mm F/1.8
115mm F/1.8

Nikon 58mm F/1.2
133mm F/1.2

Nikon 85mm F/1.4
200mm F/1.4

Nikon 135mm F/2.0
310mm F/2.0

Nikon 80-200mm F/2.8
185-460 F/2.8

Zeiss 300mm F/4
700MM F/4

Now remember the Great Akira Kurasawa used a 500mm lens on interior close up shots in several movies. One being Red beard. This movie has some awesome shots in it.
I know wide angle shots will be an issue on the blackmagic cinema camera. But I hope new lenses will come out and maybe someday BMD will release a micro Four thirds mount.

Can you imagine what a 135mm F/1.2 would cost?
what about a 200mm F/1.4 People would kill for this lens.
What about a 300mm F/2.0? maybe $15,000 US
What about a 700mm F/4.0 Ziess?

I am dying to start shooting...

syberfilm
04-25-2012, 10:50 PM
Ivan that is an awesome point. That makes alot of sense. Glad you brought this to our attention.

Barry Green
04-26-2012, 12:47 PM
That's why I tried to advocate the use of the Cinema Crop Factor when comparing these new cameras to cinema cameras.

"Crop Factor" is already taken, and everyone knows that means in reference to a "full frame" sensor, but that has practically zero to do with the last 100+ years of filmmaking. The Normal35 (not Super35) sensor size (22mm wide) has been THE standard that the vast majority of movies have been shot in. Super35 has caught on more in the last decade or so, since the advent of the Digital Intermediate, and is obviously becoming the standard in the digital cinematography field. There's not that much difference between Normal35 and Super35, and in fact most of the digital sensors are using a size that's about exactly halfway inbetween the 22mm of Normal35 and the 24.9 of Super35; it looks like 23.6 is the digital cinema standard size now, and seeing as that splits the difference between N35 and S35, we should just use that as the baseline.

Using a 35mm cine sized sensor, the standard lens kit is usually something like 25, 35, 50, and 85mm, and if you need wide-angle shots, you usually go for an 18mm.

Since the BMC has about a 1.51 Cinema Crop Factor, you'd need lenses that are about 1.5x wider to get equivalent field of view.

That would make the equivalent "standard lens package" a set of 16.5mm, 23mm, 33mm, and 56mm. Those are odd sizes, and close enough, that I think we could just call it 18, 25, 35, and 50 and be done with it. Then, for wide angle shots, you'd want a 12mm.

Finally, to complete the cinema look, some of us will want to be able to match the depth of field of the BMC to a 35mm cine camera, and to do so, you'll need to open up the f-stop about one stop to match the depth of field. Many cinema films are shot around an f/2.8 to f/3.4, so you'd probably want to look at lenses that open up to at least f/1.4, because then when you stop down a stop to sharpen the lens up, it'll still be a stop more open than what is commonly used.

As such, it's one more reason why an m43 version would be so sweet -- you could get the HyperPrime 12mm/f1.6 (http://www.adorama.com/SLR1216MFT.html), Nokton 17.5mm f/0.95 (http://www.bhphotovideo.com/bnh/controller/home?O=&sku=855215&Q=&is=REG&A=details), Nokton 25mm f/0.95 (http://www.bhphotovideo.com/c/search?Ntt=nokton+25mm&N=0&InitialSearch=yes), Zeiss 35mm f/1.4 (http://www.bhphotovideo.com/c/product/733913-REG/Zeiss_1871764_35mm_F_1_4_Distagon_T.html), and Zeiss 50mm f/1.4 (http://www.bhphotovideo.com/c/product/583975-REG/Zeiss_1677_817_Normal_50mm_f_1_4_ZE.html) and have a complete set of primes that cover the whole range of conventional cinema focal lengths, with shallow-enough DOF to match cinema 35mm looks, all with (at least from 17.5mm+) exquisite manual control and gorgeous glass and tremendous build quality. (can't speak to the SLR Magic 12mm, I haven't used it and don't know if it's of comparable imagery and build quality to the others).

Those are some pricey lenses (most of them over $1000) and the Noktons and HyperPrime won't work on the BMC's Canon EF mount. I'm sure other folks will have suggestions for less expensive fast 35mm and 50mm lenses, but I don't know how we're going to get a fast wide on the BMC.

bumkicho
04-26-2012, 01:13 PM
@Barry,

So if I was shooting with 16mm f2.8 lens on BMC, then it would be a bit wider but similar to cinema (normal35) 24mm f4? And my 50mm f1.4 would be similar to 80mm f2.2?

I assume, however, the amount of light to the sensor will not be different, correct?

Barry Green
04-26-2012, 03:46 PM
So if I was shooting with 16mm f2.8 lens on BMC, then it would be a bit wider but similar to cinema (normal35) 24mm f4?
It wouldn't be any wider, it would pretty much look the same.


And my 50mm f1.4 would be similar to 80mm f2.2?
Yes. If you put an 80mm lens at about f/2 on a cinema camera, and a 50mm lens at about f/1.4 on the BMC, the resulting images would look pretty much the same (as long as you compensated for the exposure difference by using an ND filter or something similar).


I assume, however, the amount of light to the sensor will not be different, correct?
The amount of light to the sensor would definitely be different, because one is allowing light in to an f/1.4 aperture, and the other is allowing it in only to f/2. So you would need to put a one-stop ND on the BMC to really make them about equivalent in imaging.

Osslund
04-26-2012, 04:14 PM
The thing with lenses is you have to take into account the distance from the camera to the subject. With a crop use of a lens you have to change the distance between camera-subject and then background blur becomes very different. It's just not to calculate with a crop factor and expecting the same result by just changing F number and framing.

To me the thing with this camera is not any narrow DOF but the wide dynamic range which I think makes this camera look more like a film camera than most of the other larger sensor cameras.

Barry Green
04-26-2012, 04:47 PM
The thing with lenses is you have to take into account the distance from the camera to the subject. With a crop use of a lens you have to change the distance between camera-subject and then background blur becomes very different. It's just not to calculate with a crop factor and expecting the same result by just changing F number and framing.
What I'm describing is going to result in identical imagery. If you change the distance from the camera to the subject, that changes everything -- perspective, background, everything. But if you keep in the exact same position, use the appropriate focal length to overcome the crop, and then open the iris to compensate for the DOF difference, you can get identical imagery as the larger-sensor camera.

Ivan
04-26-2012, 07:12 PM
That's why I tried to advocate the use of the Cinema Crop Factor when comparing these new cameras to cinema cameras.

"Crop Factor" is already taken, and everyone knows that means in reference to a "full frame" sensor, but that has practically zero to do with the last 100+ years of filmmaking. The Normal35 (not Super35) sensor size (22mm wide) has been THE standard that the vast majority of movies have been shot in. Super35 has caught on more in the last decade or so, since the advent of the Digital Intermediate, and is obviously becoming the standard in the digital cinematography field. There's not that much difference between Normal35 and Super35, and in fact most of the digital sensors are using a size that's about exactly halfway inbetween the 22mm of Normal35 and the 24.9 of Super35; it looks like 23.6 is the digital cinema standard size now, and seeing as that splits the difference between N35 and S35, we should just use that as the baseline.

Using a 35mm cine sized sensor, the standard lens kit is usually something like 25, 35, 50, and 85mm, and if you need wide-angle shots, you usually go for an 18mm.

Since the BMC has about a 1.51 Cinema Crop Factor, you'd need lenses that are about 1.5x wider to get equivalent field of view.

That would make the equivalent "standard lens package" a set of 16.5mm, 23mm, 33mm, and 56mm. Those are odd sizes, and close enough, that I think we could just call it 18, 25, 35, and 50 and be done with it. Then, for wide angle shots, you'd want a 12mm.

Finally, to complete the cinema look, some of us will want to be able to match the depth of field of the BMC to a 35mm cine camera, and to do so, you'll need to open up the f-stop about one stop to match the depth of field. Many cinema films are shot around an f/2.8 to f/3.4, so you'd probably want to look at lenses that open up to at least f/1.4, because then when you stop down a stop to sharpen the lens up, it'll still be a stop more open than what is commonly used.

As such, it's one more reason why an m43 version would be so sweet -- you could get the HyperPrime 12mm/f1.6 (http://www.adorama.com/SLR1216MFT.html), Nokton 17.5mm f/0.95 (http://www.bhphotovideo.com/bnh/controller/home?O=&sku=855215&Q=&is=REG&A=details), Nokton 25mm f/0.95 (http://www.bhphotovideo.com/c/search?Ntt=nokton+25mm&N=0&InitialSearch=yes), Zeiss 35mm f/1.4 (http://www.bhphotovideo.com/c/product/733913-REG/Zeiss_1871764_35mm_F_1_4_Distagon_T.html), and Zeiss 50mm f/1.4 (http://www.bhphotovideo.com/c/product/583975-REG/Zeiss_1677_817_Normal_50mm_f_1_4_ZE.html) and have a complete set of primes that cover the whole range of conventional cinema focal lengths, with shallow-enough DOF to match cinema 35mm looks, all with (at least from 17.5mm+) exquisite manual control and gorgeous glass and tremendous build quality. (can't speak to the SLR Magic 12mm, I haven't used it and don't know if it's of comparable imagery and build quality to the others).

Those are some pricey lenses (most of them over $1000) and the Noktons and HyperPrime won't work on the BMC's Canon EF mount. I'm sure other folks will have suggestions for less expensive fast 35mm and 50mm lenses, but I don't know how we're going to get a fast wide on the BMC.

Good points, and I think we are trying to achieve the same thing
Whatever we compare it to, it should be consistent... as long as we are all aware of the frame of reference.

But but Normal 35 are you referring to standard academy format? If so the 22mm is nearly identical to the 7D which is interesting...

In regards to S35, it has been popular a bit longer than 10 years. It was developed in the 50s, then revived in the 80s...

What I find coolest is that super 35 actually is academy 35, but with the extended width once the audio track was cut out and the film frame extended to the edge, and of course "cropped down" to get more frames per ft (I am racking my brains here, but I believe that is close?)

Ivan
04-26-2012, 07:16 PM
What I'm describing is going to result in identical imagery. If you change the distance from the camera to the subject, that changes everything -- perspective, background, everything. But if you keep in the exact same position, use the appropriate focal length to overcome the crop, and then open the iris to compensate for the DOF difference, you can get identical imagery as the larger-sensor camera.

This will result in the same frame size with the similar DOF... but

Using the same lens the image at max aperture the image will be noticeably softer than on s35 2.8. Also the quality and type of the bokeh will be different amongst different lenses. But for all intents and purposes the images should closely, but certainly not identical.

Cheers

Ivan

Grug
04-27-2012, 01:19 AM
Barry and Ivan, whilst you make a perfectly legitimate point about the 'crop' reference making more sense in comparison to S35mm, I think the people have pretty much spoken by this point - FF35/Vistavision is the reference point.

It came in when stills photographers were migrating to DX/ASP-C-sized sensor cameras from film, and (for better or worse) it's stuck. I think it's easier at this point to simply stick with the single reference point so that people can avoid any additional confusion.

Barry Green
04-27-2012, 11:46 AM
The term "crop factor" is usually used in reference to FF35, yes. But to cinema shooters, FF35 is an irrelevant point of reference, and those who have shot primarily on cinema cameras may be interested to know how the BMC's sensor compares to what they're used to.

So hey, everyone can be happy, just pick the crop factor that is relevant to your point of view. If you're an FF35 shooter, and you think in terms of FF's angles of view, then use 2.3x. If you're an S35 shooter and want to know how the BMC's field of view will compare to what you're used to, then use the 1.5x number.

imdjay
04-27-2012, 09:09 PM
maybe this will clear a thing or two up, maybe not. maybe i just like to hear my own voice.... either way i'll post it since it visualizes what's being discussed:



https://vimeo.com/19940853

Kavadni
04-28-2012, 02:27 PM
maybe this will clear a thing or two up, maybe not. maybe i just like to hear my own voice.... either way i'll post it since it visualizes what's being discussed:



https://vimeo.com/19940853

:) perfect