3 prime lenses set for BMCC2.5mFT

Hi guys, I'm trying to figure out an ideal set of prime lenses for BMCC 2.5K mFT.

My point of reference is Canon cine set: 4 lenses: 14mm, 24mm, 50mm, 85mm.
And the Zeiss CP.2 4-lenses set: 21mm, 35mm, 50mm, 85mm.
Almost all lenses have T1.5

But I have to consider the 1.6 crop factor of the Super35 sensor of a C100/FS100, that means...
22mm, 38mm, 80mm, 136mm for Canon;
34mm, 56mm, 80mm, 136mm for Zeiss.
DoF, T2.4

Now, I have to find out a set o prime lenses that maches the cine-sets profile.
BMCC2.5K has 2.4 crop factor, so to get closer to T2.4-DoF I have to look only at Voigtlaender and SLR Magic because their f/0.95 lenses become f/2.3-cropped-DoF.
The mFT sets are:
SLR Magic 12mm, 25mm, 50mm
Voigtlaender 17.5mm, 25mm, 42.5mm

On BMCC2.5K, the 2.4 crop factor transforms the focal lengh into...
29mm, 60mm, 120mm for SLR Magic
42mm, 60mm, 102mm for Voigtlaender

Comparising cine-sets with mFT-sets:
22 38 z56 80 136 [cropped cine-set]
29 v42 60 v102 120 [cropped mFT-set]

I suppose to start from the ends: 29 (12mm) and 120 (50mm).
At this point, I'd like to say that I need only another lens in the middle, 60 (25mm), and a 3-lenses-set would save my budget!
But with 29 60 120 I give up the 38-42 range, and I give up also the 80-102 "portrait" range.

Which is your advice, guys?
Do you think I could do almost anything with...
29 60 120 (and my budget thanks!), or I need something like...
29 42 102 120, or
29 60 102 120?

Thanks for your help.

I thought the crop factor was 2.3?

Crop factor confusion seems to be prevalent with me also. I tried to research on it a bit but in vain. best accident lawyer

Crop factor is for stills, comparing them to a 65mm negative (35mm film running sideways in an SLR).

For Cine, use Super 35 16:9 as your reference 1.0, and calculate AOV of lenses in comparison to that.

For example, the diagonal of Super 35 = 28.5mm, and the diagonal of the BMDCC = 18.14mm
Therefore, the CineCropFactor for the BMDCC = .64

A "normal" lens has an AOV of 45º, which translates to a 30mm lens on S35.
To get the same AOV, you multiply the S35 lens focal length by the CineCropFactor of .64 = 19.1mm

So a 20mm lens is going to be close to normal.

To get the best results, stop comparing your cinematography to 5D shooting, and look at Hollywood movies instead. Look up your favorite films, directors and DPs in American Cinematographer magazine. They commonly talk about their lens choices and focal lengths. You'll be surprised at how few lenses they use on a picture.

Hope that helps.

Well, actually my reasoning took the point of my question away...
But really my question was simpler:
Do you think the SLR 3-lenses set (12mm, 25mm, 50mm) on BMCC2.5K is sufficiently varied to test more or less any kind of shot (from long-shot to close-up)? Or do you think I need 4 lenses minimum?
Thx a lot.

You need as many lenses as you need for your shooting style.
Not that I do this too much in cinematography; but in photography, I basically live on my 43~86mm zoom on my Nikon-- but I keep it almost always @ 43mm because that's what I like in stills.

Now, let's go over to cinematography, normally you want at least 3 lenses, a wide, a normal (or not so wide if you're me) and a long (or normal if you're me) in the least. However, depending on what you're actually shooting and how you may need to bring more and more lenses into the picture; but there is no cut and dry. On one film I may be living on a 32 or 35mm for 90% of the shots. On another I may be using a 100mm a 180, a 14 ect ect.

Just from memory, on my last 2 shoots (super 35 sizes) my main lenses were as follows:

35mm and 18mm lomos paired to a 60D

85/50/35 Compact Primes on a RedOne.

Ok, so now that's out of the way, here's the real rub, start with as few lenses as you think you'll need, especially if you don't know how well you'll like your particular lenses. Were it me and I was shopping 'round for BMCC lenses, I would certainly want to start on the wide end and work my way in to the telephoto, so something like a 12mm would be the first lens I'd pick up because, let's face it, with this odd sensor size, it's a bit hard to get something wide enough (though I'd probably go with a 8mm Rokinon on a budget). From there I'd work my way in slowly building up my kit and renting what I need until such time as I KNOW for my style of shooting, these are the lenses I tend towards.
Site like LensRental can be a life-saver for things like this as they're pretty cheap all in all and offer up most of the lenses you'll be looking at to purchase. This saves you from spending some cash on some glass you may or may not like nor really use.

Crop factor is for stills, comparing them to a 65mm negative (35mm film running sideways in an SLR).

crop factor is for full frame sensor (36mm x 24mm)

For Cine, use Super 35 16:9 as your reference 1.0, and calculate AOV of lenses in comparison to that.

right idea

For example, the diagonal of Super 35 = 28.5mm, and the diagonal of the BMDCC = 18.14mm
Therefore, the CineCropFactor for the BMDCC = .64

when people are wanting "wide" shots they need only concern themselves with the width of the sensor (Super 35 is 24mm BMCC is 15.81 this results in a ~0.66)

A "normal" lens has an AOV of 45º, which translates to a 30mm lens on S35.
To get the same AOV, you multiply the S35 lens focal length by the CineCropFactor of .64 = 19.1mm

So a 20mm lens is going to be close to normal.

To get the best results, stop comparing your cinematography to 5D shooting, and look at Hollywood movies instead. Look up your favorite films, directors and DPs in American Cinematographer magazine. They commonly talk about their lens choices and focal lengths. You'll be surprised at how few lenses they use on a picture.

Hope that helps.

or if you want a wider shot, back away from your subject...

Wide lenses is more than just a wider shot; see Terry Gilliam, for example.
Also, often you cannot just back away.

Wide lenses is more than just a wider shot; see Terry Gilliam, for example.
Also, often you cannot just back away.

yes I know, but its usually the easiest things to do.

Dunno if i personally agree with that TZuck. if anything, I can almost always move the camera in closer -v- further away on locations, unless i'm shooting outside. Or so has been my experience.

or, just buy a wide angle adapter... and though some may not agree with moving away from the subject, its more in the spirit of improvising, and working with what you have. I've found working with limitations inspire creativity (personal opinion) but this thread is concerning itself with prime lenses on a crop sensor. just wanted to clarify the math (see few posts above), as people like to concern themselves with numbers. might as well make sure those numbers are correct right?

Just about the word "adapter", what about Macro_adapters?
I'm just considering to approach Macro possibilities without throwing money for a Macro_lens.

There are 4 options:
1. Tiffen Close-up lens set (http://www.tiffen.com/displayproduct.ht ... mnum=77CUS)
2. Raynox DCR-5320PRO Macro converter (http://www.raynox.co.jp/english/dcr/dcr ... /index.htm)
3. Fotodiox Macro Reverse Ring Kit (http://fotodioxpro.com/index.php/fotodi ... d7000.html)
4. Fotodiox Macro Extension Tube Set (http://fotodioxpro.com/index.php/camera ... 3-g10.html)

On the chart, I'd prefer the 4th option since it doesn't add glass and you can use the lens hood (while it's impossible with reverse option).

Do you agree?

Vivitar makes a combined wide-angle and macro adapter which I use on my GH2 for video. It works well enough and it less than $20.

For real macro, you'll really enjoy macro lenses. And in fact, with the smaller sensor on the BMCC things like a 55mm macro become very attractive (-v- the 100 mm macros you typically need on s35mm cameras)

Question: when you simply add a IR filter (i.e. Tiffen T1), does it add some stop to the lens aperture? For example: an f/0.95 lens, with the Tiffen T1 IR becomes f/1.8 or remains f/0.95?
Thanks

Question: when you simply add a IR filter (i.e. Tiffen T1), does it add some stop to the lens aperture? For example: an f/0.95 lens, with the Tiffen T1 IR becomes f/1.8 or remains f/0.95?
Thanks

The more stuff you put in between the sensor and the subject will reduce the amount of light, however in cases of just a clear filter the light loss is negligible.