Why do you use a lens that you do?

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Jim Rudolf

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Why do you use a lens that you do?

PostMon Mar 20, 2017 8:04 pm

Hello all,

I'm getting into a whole new world of primes. My background is ENG style shooting. You have one killer zoom lens, pre focus on the eyes and roll. That was many years ago. Now I'm playing with Primes, just because of the challenge, and overall it gives me the best picture.

I have Canon Zoom 24-105 for my run and gun stuff. But for my staged stuff. A Rokinon 24 and 50. I guess I'm not sure what to use for certain scenarios. Is there a rule of thumb. Do I use the 24 for interviews, close-up hand work, table top stuff, And the 50 for outside vista shots, blocked action shots. Just curious what you use your lens for. How do you decide what lens to put on?


Thanks!

Jim
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rick.lang

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Why do you use a lens that you do?

PostMon Mar 20, 2017 8:17 pm

Which camera are you using with those prime lenses? If we know your camera, it's easier to give relevant advice.



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Denny Smith

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Re: Why do you use a lens that you do?

PostMon Mar 20, 2017 9:15 pm

Another approach is to have a "normal" angle of view (40-45 degree) lens for most shots, a 35mm on a S35 sensor like the Ursa Mini, or a 16-17mm on the Pocket camera gives you this AOV. Then you want a "wide" angle(16-25mm S35) for establishing shots and a short tele for close up shots (50-85mm for S35).
But as Rick pointed out, knowing which camera you are using, will help in making specific recommendations. :mrgreen:
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Jim Rudolf

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Re: Why do you use a lens that you do?

PostMon Mar 20, 2017 9:42 pm

Good points. I have the URSA mini 4k.

Denny, what do you mean by AOV?

Jim
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Craig Marshall

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Re: Why do you use a lens that you do?

PostMon Mar 20, 2017 9:45 pm

Like the OP, I cut my teeth shooting ENG and those fast, parfocal servo zooms are hard to beat but for modern, large sensor cameras, my pick is the classic Zeiss 'Contax' series. These have a huge following among the RED enthusiasts too with many claiming that they offer far superior performance to Zeiss CP.2s.

Of course, Contax primes are full frame 'stills' lenses BUT they feature a large focus rotation in the correct direction, ultra close focus, minimal breathing and unlike many modern lenses, the Contax series are low contrast lenses so benefit greatly from today's post production Grading practices. No need to shoot Log.

Among the Contax primes, the 100mm F/2.0 'Hollywood' is highly sort after as is the wonderful 21mm Distigon F/2.8. The latter is my all time favourite prime as it is fast (f/1.9 via a focal reducer on S-35) and with a 91 degree field of view, it pretty much sees what your eye sees without any barrel distortion and stopped down a bit, your focus is from about 30cm to infinity. It is the wide lens I use when I don't want the viewer to notice the 'lens'...
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Denny Smith

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 2:37 am

Jim Rudolf wrote:Good points. I have the URSA mini 4k.
Denny, what do you mean by AOV?
Jim


Sorry, AOV = angle of view, i.e. 45-degrees for a "normal" focal length lens, which on your UM 4K is 30mm. So a 16-18 would give you a wide shot, your 24mm is close enough to a 30mm for your normal AOV, and 50-85mm short tele portrait lens. The wider the focal length, the wider the AOV of a lens on a sensor format size.
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Last edited by Denny Smith on Tue Mar 21, 2017 4:20 pm, edited 1 time in total.
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Jim Rudolf

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 1:18 pm

Thanks Denny for the clarification. So I have a 24mm and a 50mm. Do you think I really need a 35mm to complete a set? I do have the Canon 24-105. So I guess that should cover anything in between.

The thing I like about primes is that you really have to think about setting up your shot. I have one more question on the primes. On my 24mm for example, is reads 1.5/24mm. What does the 1.5 stand for?

Thanks to all for the great information.

Jim
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Denny Smith

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 3:54 pm

The 1.5 is the max f/stop which is an odd f/1.5 (normal stop is f/1.4, but Canon is trying to be more accurate than just calling it f/1.4). A 35mm is not a focal length used in Standar 35 format (UM 4K), but would give you a slightly "long" normal shot compaired tomthe wider AOV of the 24mm.
A good starting set would run 18mm, 24 to 30mm, 50mm, which will give you the basics.
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Last edited by Denny Smith on Tue Mar 21, 2017 4:25 pm, edited 1 time in total.
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rick.lang

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Why do you use a lens that you do?

PostTue Mar 21, 2017 4:01 pm

So with your 4K sensor, your 50mm is your best 'portrait' or medium close up lens and the 24mm is a wide normal. The 35mm would be a long normal. So it's up to you if you want to add the 35mm. If you do much interior work, you may want to consider the Rokinon 16mm before the 35mm. As you mentioned, the zoom can act as a variable prime lens, but you likely need something wider. Several folks here are happy with the 16mm including Vic Harris et al.

Personally, I prefer the 'long' look, more detached and the lens doesn't become part of the story like it can in a wide lens like the 16mm. But some directors like to go wide as the camera (our eyes) becomes another participant in the group being filmed, rather than a long lens that's like a hidden voyeur!

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Denny Smith

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 4:13 pm

Rick, 16mm would be more like Ultra Wide on the UM 4K! I put a 12mm on my AF100 (MFT) which is the same AOV, and was it ever wide. Unless you want to put the viewer right in the middle of the scene (shot), a less wide angle would be more useful, like a 16 or even a 18mm, which I find a nice wide on this format, and a good 18mm can be had with a Zeiss ZE 18mm (Canon mount), used ones are available at a nice saving too. A 18mm would be close to the same AOV as a 24mm on the UM46, and is more of standard wide angle for most shots needing a nice wide.

I would give the 35mm a skip for now, and as you recommended, get a wide angle lens next.
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rick.lang

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 5:29 pm

Remember the 'crop factor' on the 4K sensor is about 1.6x so 16mm is like a 25mm on 'full frame' 135 film. Yes, it's wide but can be effective. For interiors, I've used 18mm and wished I had something wider. But 18mm is a nice pairing with the 24mm but I don't think Rokinon does 18mm so I went with the excellent 16mm. That's my thinking.


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rick.lang

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 5:34 pm

On the 4.6K sensor, 18mm is likely as wide as I plan to go when SLR Magic releases it sometime next year I suspect. 'Crop factor' on the 4.6K is 1.42x so that's quite a bit wider view than 4K sensor.

I'm off on a trip for a few days. Sadly I have the car jammed full of females and their bags so no room for the camera gear! Need to look into Thule car storage... another indispensable bit of kit for camera shooters.


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Guy Fiorita

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 5:52 pm

My advice would be to rent a full set of 5-6 primes, shoot a project and see which ones you like/use most.

The issue with using the 24-105 to 'fill in' where your primes are lacking is you're losing a few stops of light (its a f4 v the f1.5) and it if you grade your footage its going to take more work to match the primes. You get a matching set because they will all render color the same way and will be easier to match in the grade.

In addition to all that AOV and FOV stuff, different lenses shape faces differently. Generally you don't want to use a wide lens for a close up because it narrows the face and looks weird (and you have to have the camera right in your talent's face). Here's a gif that gives you an idea:

https://twitter.com/Booooooom/status/758057451656654848

Its also why everyone looks thinner on a webcams/facetime. Its a 20mm-ish lens.

I'm also a fan of contax/zeiss and used a buying guide on another forum to assemble a set that I love.
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Jim Rudolf

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 6:45 pm

Thank you all for the great info. Now I have a better understanding on the primes. And how to select a lens depending on what shot I want. Renting lens is a great idea!

Ok, one more question. I also have a Ronin M stabilizer. Trying to figure out the best lens for that. If 30mm or 35mm is the closest to human view of angle. I'm thinking that would be the best lens to use for that setup.
Thoughts?

Jim
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Craig Marshall

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Re: Why do you use a lens that you do?

PostTue Mar 21, 2017 7:35 pm

THE CONTAX “Standard Primes” or GIMBAL PRIMES

18 f4
28 2.8
35 2.8
50 1.7 / 50 1.4
85 2.8
100 3.5
135 2.8

Contax Zeiss did the world a favor and made "budget/travel" versions of many focal lengths. Small, lighter and more affordable, these lenses seem designed not just for cost conscious professionals, but also for travel photographers who often needed to save space, and keep things simple.

To that end, most of these primes are almost IDENTICAL in SIZE/SHAPE/WEIGHT...so much so it's hard to believe it's a coincidence (they almost seem designed to be "swappable" in a travel case).

THESE primes in particular are almost identical in shape/size/weight:

18 F4
28 2.8
35 2.8
50 1.4
85 2.8

Why is this important? Well in this age of gimbals, where lens size/weight is so important to balancing your rig, having a set of tiny LIGHT WEIGHT Zeiss primes that also happen to be evenly SIZED...is incredibly convenient. In fact, Movi shooters like Chris McKechnie are able to swap these primes mid shoot and barely make any adjustments to their gimbal...which is a MASSIVE time saver.


From Nick Morrison's 'Contax' thread on the RED Forum.
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