I can't tell the difference between primes and zooms and how primes are 'better'.

I

ironpony

Carbonite Member
I was wondering if I should get primes for my next project, which I want to make a high quality impression on. And I keep hearing from more experienced people that primes produce a sharper, crisper image. For my last short film the DP used primes and zooms and switched back and forth, from shot to shot in a couple of scenes. When I play them back I cannot tell the difference as it cuts from one angle of an actor to another, how primes are crisper. Everyone says crisper, but it's hard to get some elaboration on it? Could you elaborate? Thanks. I also want to keep practicing to make a feature in the near future. Would I need primes for that to make a good impression, or would zooms suffice? Some say there are zooms out there that are just as good, and some disagree? Who is right, and what exactly are the precise differences, since I cannot seem to tell.

Perhaps the prime the DP was using was not a really good sharp prime... But I can also think of having again to mix lenses, and if I got a super sharp prime, and then mixed it with a zoom, will the audience notice? Thanks.
 
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It's down to physics. Zooms are always going to be a compromise - as focal lengths change, it's very difficult to to maintain the optical path at the highest quality. What seems to happen is that at some focal lengths, the best optical performance is at the centre, and the very edges of the frame are poorer. Sometimes the lower quality means simply softer images, but often you start to get odd colour fringing and of course straight lines becoming curved as barrel or pincushion distortion becomes evident. Some lenses 'breath' - where adjustments in focus change the focal length slightly. Cheaper zooms tend to have more distortion and more breathing. It is possible to make zooms with better optical performance by using compensating lenses inside that also move to counteract the optical compromises - but these also tend to make the light loss through the glass greater. A prime lens with a preset angle of view are optimised for that one focal length - so usually offer less distortion and are faster, handy if you need to use shorter exposure times or high shutter speeds. Don't forget they're not new to video - early video cameras had prime lenses on the front turret. However, to many people (me included) a zoom an essential tool. With a prime the camera has to be able to move to change the image size. This also helps give the image a 'specialness' - which I firmly believe is really just the audience feeling the changes in perspective when the camera moves towards or away from the subject. If you use primes and move the camera, the resulting images when edited together look different and I think the brain interprets this as camera movement. It tends to remind of of the cinema, where this is pretty well the standard. Video tends to use less physical camera movement because with the zoom, it's not quite so important. This adds to the cinematic experience (yuk, I hate that word!).

I also suppose the end medium is important. I doubt extra lens sharpness will be obvious on a DVD, but maybe on Blu-Ray.

Good glass, with few optical defects always does look nicer. A good quality zoom, used on the lenses best focal length could look very good, negating the need for a prime - which we must remember is a recently discovered old trick. As sensor sizes go up, people are starting to be very critical of any camera item that has a compromise aspect - and are trying to eliminate everything detrimental to image quality. I'd like to see a big box lens stuck onto one of the newer cameras and see what results people achieved with many tens of thousands of pounds worth of glass on the front?
 
Okay thanks. But why do you think that video tends to use less camera movement? These days we are getting more than ever. I am also watching my scene on 1080p and still cannot tell the difference.
 
Video compression is on magnitudes more important than lens quality for the final image.
You need high-res video and high-quality video compression (ideally lossless) to take benefit from high-quality lenses (in terms of crispness, that is).
 
of course some primes are faster, lighter, and less bendy as pointed out above

I think this is particulary obvious at the wide end

My FS100 has 3 options at 18mm

18-55 Nex5 kit lens very bendy
18-200 FSkit lens - quite bendy
18mm nikkor prime - very straight

S
 
As a purely philosophical point. To me, it plays into the "lazy" cinematography we talked about in another thread. Not making a moral judgement on anybody, but in my world when you want to change the framing you change the lens, you move the camera. The act of being able to zoom to 53.2 mm or whatever to re-frame the shot, Just not the way I want to work. It's an arty farty thing.
 
I don't think zoom lenses are necessarily a bad thing. PL mount cinema zoom lenses certainly exist. Usually, the idea of primes is for their speed/sharpness, i.e. a f/1.2 at f/2.8 will have better performance than a fixed f/2.8 zoom lens wide open.
 
gonzo_entertainment said:
As a purely philosophical point. To me, it plays into the "lazy" cinematography we talked about in another thread. Not making a moral judgement on anybody, but in my world when you want to change the framing you change the lens, you move the camera. The act of being able to zoom to 53.2 mm or whatever to re-frame the shot, Just not the way I want to work. It's an arty farty thing.
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Yeah, but you can do exactly the same with a zoom. "Change focal length, move the camera."
This is not a property exclusive to prime lenses.

In the world of crappy video prime lenses advantages are limited to faster apertures, (potentially) better OOF rendering, better focus rings, smaller size.
Zooms, on the other hand, mean convenience and color matched shots.
 
gonzo_entertainment said:
As a purely philosophical point. To me, it plays into the "lazy" cinematography we talked about in another thread. Not making a moral judgement on anybody, but in my world when you want to change the framing you change the lens, you move the camera. The act of being able to zoom to 53.2 mm or whatever to re-frame the shot, Just not the way I want to work. It's an arty farty thing.
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On the other hand because of time and budget restrictions many productions have once again started using zooms to save time on set. The Optimo 24-290mm has become a real workhorse.
 
Absolutely. My DP bitches about it from time to time. It's a "choice" on my part. Wouldn't impose it on anybody else. In art process matters. How you made it is sometimes as important as the end result.
 
Sweet renting a pair of Optimo zoom lenses though, they look great and aren't too slow either.
 
The optimo zooms are fantastic. Modern cinema zoom lenses are fantastic. No need to use a prime simply for "artistic" sake . If you have a legitimate reason then sure, use primes. But changing lenses for the sake of changing lenses just wastes time to me.
 
"No need to use a prime simply for "artistic" sake "

For you.

No reason to do a LOT of things in "art". You do them because it's part of the aesthetic or process or whatever want to represent. Again, I see why people use zooms, I understand when they can be helpful, I choose (right now) not to use them. I don't dog anybody else for choosing differently.
 
ironpony said:
Okay thanks. But why do you think that video tends to use less camera movement? These days we are getting more than ever. I am also watching my scene on 1080p and still cannot tell the difference.
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By 'video' I'll assume you mean TV and perhaps 'event video' or 'industrial video'... the use of a Zoom in event and industrial video just is cheaper/simpler than using a set of prime lenses. TV production for broadcast is premised on the concept of 'cheap production'... the use of dialog heavy scripts, limited locations, and in the studio use of three cameras just 'calls' for zoom lensing.

At the core... a zoom lens has more optical elements and at each surface of an optical element there is image 'degradation'. There are methods, very good methods, to deal with the various types of losses to image quality, but for a give prime, there are fewer places for such loss.

The most 'obvious' place where image degradation occurs is in the 'edge contrast'. A 'flat' surface with no edges will not show much of a difference between zoom and prime. But at edges there will be a lessening of contrast, which the human visual perception system 'interprets' as 'sharpness'.

I do agree that for most 'internet' and perhaps even some DVD distributions this sort of 'quality' factor may not be as big an issue as it is made out be by some... With Bluray and current 2K image capture, along with 10 bit intensity resolution... things may be more 'obvious' when shooting zoom vs. prime.

I don't know if using an unsharpe mask filter is done 'typically' on moving pictures media, but I use that on stills and have used it on my moving pictures output to 'clean up' the edge contrast just 'slightly' to give the impression of more sharpness...

Unsharp mask does not make an image 'sharper', but just increases the edge contrast which is interpreted by the human viewer to be 'sharper'...
 
gonzo_entertainment said:
"No need to use a prime simply for "artistic" sake "

For you.

No reason to do a LOT of things in "art". You do them because it's part of the aesthetic or process or whatever want to represent. Again, I see why people use zooms, I understand when they can be helpful, I choose (right now) not to use them. I don't dog anybody else for choosing differently.
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Dont mean to offend. I guess that came across a little harsh. I was just thinking about it practically, as time is always the most expensive thing on set. I get what your saying about artistic processes. I just found it curious because filmmaking is such a large collaborative undertaking as opposed to say painting where an artist may choose to take time to do anything he/she wants to get in the "zone" because they are working alone...
 
On the lower end, I have two zooms that I use with my FS-100 that I really like. I have a Vivitar series 1 (Cosina manufacture) 28-105mm f2.8-3.5 zoom and a Vivitar Series 1 (Kiron manufacture) 70-210mm f3.5-5.6 zoom. My standard lens kit is Nikon primes in 20mm, 24mm, 35mm, 50mm and 100mm. The Vivitar zooms are very comparable in image quality to the Nikon primes and I use the 28-105 quit a bit as a variable prime. I really like that lens. I would use it as a run and gun lens, but I would not leave home without my primes. My biggest issue is with speed. My fastest lens is a Nikon 50mm f1.4 and the rest are all f2.8. Sometimes the f3.5 at the long end of the 28-105mm is limiting TO ME.

EDIT: For wide angle, I do have that Sony E-mount 16mm f2.8 lens, but I don't really care for it. It is noticeably less sharp then all of my other lenses. The 20mm Nikon is plenty wide for my taste and is not very "Bendy" at all.
 
No offense taken at all.
Just making sure the other point of view was clear. I'm all for expedience and efficiency, but sometimes putting yourself in a box aids creativity more than being totally free. Like verse poetry, where the art is expressing something within the confines of the form. As I said, arty farty BS for the most part, but I subscribe to some of it (when I choose to).
 
I don't spec primes in my camera packages any more unless there are very specific reasons for doing so. Those would include shooting faster than T2.8 for the look (as the classic reason of needing the added exposure for night exteriors is all but buttoned up by today's fast sensors) and specialized rigs where the lightest/smallest camera possible is necessary, or for a specialized look like anamorphics. My typical package is the two Arri/Fujinon Alura T2.6 zooms (18-80 and 45-250) and the Optimo 15-40 and 28-76. The Aluras are lighter and in my opinion more consistent than the Optimo 24-290 and I'm covered on the range with both cameras if I need both to be wide by swapping to the "baby" Optimos, which also cover most handheld and Steadicam needs. I'll dayplay longer primes as needed for those purposes.

While I came up with the "primes are always better" philosophy, I believe that zooms have come a very long way and my trusted lens tech has gone as far to say that a certain line of zooms (the Fujinon Premiers) bench-test as well as any prime. As mentioned above, time is the critical factor and I have not shot a project in years that I can remember where we would have been able to accomodate lens changes. Given the choice between losing a few setups out of the day and using primes, it's a no-brainer. I don't believe there is anything inherently lazy about working with zooms, unless you choose to be lazy in your usage. If I have time to move the camera to where I want, I will do so; if not, we dial it in on the lens and shoot. Sometimes there are specific compromises with primes that make you wish you had a 37.5mm because the 25 is too wide and the 50 is too tight, but oh well.
 
CharlesPapert said:
I don't spec primes in my camera packages any more unless there are very specific reasons for doing so. Those would include shooting faster than T2.8 for the look (as the classic reason of needing the added exposure for night exteriors is all but buttoned up by today's fast sensors) and specialized rigs where the lightest/smallest camera possible is necessary, or for a specialized look like anamorphics. My typical package is the two Arri/Fujinon Alura T2.6 zooms (18-80 and 45-250) and the Optimo 15-40 and 28-76. The Aluras are lighter and in my opinion more consistent than the Optimo 24-290 and I'm covered on the range with both cameras if I need both to be wide by swapping to the "baby" Optimos, which also cover most handheld and Steadicam needs. I'll dayplay longer primes as needed for those purposes.

While I came up with the "primes are always better" philosophy, I believe that zooms have come a very long way and my trusted lens tech has gone as far to say that a certain line of zooms (the Fujinon Premiers) bench-test as well as any prime. As mentioned above, time is the critical factor and I have not shot a project in years that I can remember where we would have been able to accomodate lens changes. Given the choice between losing a few setups out of the day and using primes, it's a no-brainer. I don't believe there is anything inherently lazy about working with zooms, unless you choose to be lazy in your usage. If I have time to move the camera to where I want, I will do so; if not, we dial it in on the lens and shoot. Sometimes there are specific compromises with primes that make you wish you had a 37.5mm because the 25 is too wide and the 50 is too tight, but oh well.
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I think you do have to be clear that you are speaking about cine zooms, and not the 35mm still zoom that are the ones that many people can afford... I looked up the zoom that was used for the Zacuto shootout... a Fujinon, with a price of $85K (or was it $89K...) even at 'rental' prices is out of most people's budget.

I'm sure the Fujinon zoom would have better performance than some large set of 35mm still primes... and for the price... I'd expect it... (Heck that's more than most people pay for a luxury automobile...).
 
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