What is the advantage of primes? at DVinfo.net

Dan McCain · April 24th, 2004, 01:30 PM

What is the advantage to buying a set of primes over getting a nice zoom lens? I would like to purchased a nice zoom lens ( I dont care about the zoom motion, I never zoom anyway) and have a wide range of options. Please advise me!

DAN

Rob Belics · April 24th, 2004, 02:14 PM

A zoom lens needs many more elements to operate and are mechanically "fluid" compared to primes. Hence its light handling abilities are less, resolution is less, aberrations more, and problems such as "breathing".

Dan McCain · April 24th, 2004, 02:38 PM

Will I notice a huge difference with the DVX100 footage?

Rob Belics · April 24th, 2004, 05:09 PM

Say you are focused on one person, then change focus to another person. "Breathing" is a noticeable change in the image size as if you did a slight zoom on the lens. Yes, it is noticeable on any camera that has the problem.

Dan McCain · April 24th, 2004, 06:26 PM

Is this the same as a zoom lens?

Rob Belics · April 24th, 2004, 06:48 PM

Yes and no. A variable prime could be called a "short zoom" lens. Due to their short range, like 16-30mm, all of the design variables and mechanics are easier to make solid. Not that it's easy to do and it is more expensive but the ones I'm familiar with are excellent.

Dennis Hingsberg · April 25th, 2004, 07:04 PM

I use both primes and zoom lens with my mini35. If your zoom lens does not have the same f-stop rating throughout it's zoom range - you will need to pay more attention to your lighting levels when changing zoom on the lens. You can use the iris to do this but generally not having enough light is a problem. In this sense, prime lenses "can" be better, but of course only if they too have similar f-stop ratings.

Imagine lighting a scene and then from a distance shooting it at 28mm @ a f-stop rating of 2.8. You then want a close up shot so instead of moving the camera (perhaps because the actor is sitting at a table and you are shooting directly across from him) you simply adjust the lens to 85mm. You've got your close up shot now, but the image is darker because at 85mm the lens is rated at f4.5. Even with the iris at f2.8 you are now getting f4.5 which will be a noticable change in lighting in your video. Do you change your lighting, move your camera and go back to 28mm or use a 85mm prime lens that is rated better than f2.8?

Hopefully the above example puts things in a better perspective for you. The funny thing is this example actually comes from a shoot I was doing with the mini35 today! The director's goal is to finish shooting the scene as quickly as possible, changing a lens is a piece of cake compared to changing your lighting.

Josh Brusin · May 2nd, 2004, 04:25 PM

yup. SO far the Nikons are GREAT!

Using Nikons
85mm 1.8
50mm 1.8
35mm 1.4

and a Vivitar
25-90mm MACRO 2.8 (constant 2.8)

Macro is a big +...

April 24th, 2004, 01:30 PM	#1
Dan McCain Regular Crew Join Date: Apr 2004 Location: Atlanta, GA Posts: 65	What is the advantage of primes? What is the advantage to buying a set of primes over getting a nice zoom lens? I would like to purchased a nice zoom lens ( I dont care about the zoom motion, I never zoom anyway) and have a wide range of options. Please advise me! DAN

April 24th, 2004, 02:38 PM	#3
Dan McCain Regular Crew Join Date: Apr 2004 Location: Atlanta, GA Posts: 65	what is breathing? Will I notice a huge difference with the DVX100 footage?

April 24th, 2004, 06:26 PM	#5
Dan McCain Regular Crew Join Date: Apr 2004 Location: Atlanta, GA Posts: 65	What is a variable prime lens? Is this the same as a zoom lens?

April 25th, 2004, 07:04 PM	#7
Dennis Hingsberg Trustee Join Date: Oct 2003 Location: Toronto, Canada Posts: 1,055	I use both primes and zoom lens with my mini35. If your zoom lens does not have the same f-stop rating throughout it's zoom range - you will need to pay more attention to your lighting levels when changing zoom on the lens. You can use the iris to do this but generally not having enough light is a problem. In this sense, prime lenses "can" be better, but of course only if they too have similar f-stop ratings. Imagine lighting a scene and then from a distance shooting it at 28mm @ a f-stop rating of 2.8. You then want a close up shot so instead of moving the camera (perhaps because the actor is sitting at a table and you are shooting directly across from him) you simply adjust the lens to 85mm. You've got your close up shot now, but the image is darker because at 85mm the lens is rated at f4.5. Even with the iris at f2.8 you are now getting f4.5 which will be a noticable change in lighting in your video. Do you change your lighting, move your camera and go back to 28mm or use a 85mm prime lens that is rated better than f2.8? Hopefully the above example puts things in a better perspective for you. The funny thing is this example actually comes from a shoot I was doing with the mini35 today! The director's goal is to finish shooting the scene as quickly as possible, changing a lens is a piece of cake compared to changing your lighting. __________________ Blog: www.hingsberg.com Ultimate Exposure Guides for FS5/F7S/F5/F55

April 24th, 2004, 02:14 PM	#2
Rob Belics Major Player Join Date: Apr 2003 Location: St. Louis, MO Posts: 581	A zoom lens needs many more elements to operate and are mechanically "fluid" compared to primes. Hence its light handling abilities are less, resolution is less, aberrations more, and problems such as "breathing".

April 24th, 2004, 05:09 PM	#4
Rob Belics Major Player Join Date: Apr 2003 Location: St. Louis, MO Posts: 581	Say you are focused on one person, then change focus to another person. "Breathing" is a noticeable change in the image size as if you did a slight zoom on the lens. Yes, it is noticeable on any camera that has the problem.

April 24th, 2004, 06:48 PM	#6
Rob Belics Major Player Join Date: Apr 2003 Location: St. Louis, MO Posts: 581	Yes and no. A variable prime could be called a "short zoom" lens. Due to their short range, like 16-30mm, all of the design variables and mechanics are easier to make solid. Not that it's easy to do and it is more expensive but the ones I'm familiar with are excellent.

May 2nd, 2004, 04:25 PM	#8
Josh Brusin Major Player Join Date: Nov 2003 Location: Chicago, IL Posts: 439	yup. SO far the Nikons are GREAT! Using Nikons 85mm 1.8 50mm 1.8 35mm 1.4 and a Vivitar 25-90mm MACRO 2.8 (constant 2.8) Macro is a big +...