Film Lens v.s Photo Lens

[dannylim]

What is the diff between the film lens and the photo lens?

I am new to photography... and I am considering putting money to buy some lens but ponder between film and photo lens... becasue I myself as a videographer would want to buy film lens so that i can use on both my DSLR and video camera (with DOF adaptor)...

Any advice?

 

[jaegersing]

I think maybe you mean video lens rather than film lens? (If I am wrong I apologise.)

Film lenses are very very expensive, and normal people cannot afford to buy them, they will probably rent them when needed.

Video lenses (generally) have motorised zooms that can be used during a shot. Decent video lenses will not breath too much when you adjust the focus.

Still camera zoom lenses, on the other hand, will never be motorised, so the zooming function is used mainly for framing rather than zooming during a shot. Still camera lenses also tend to breathe (i.e. like a slight zoom effect) when you focus, so if you use these for video, a rack focus shot can look a bit strange.

Still camera lenses are normally designed to focus on a 35mm film plane (not counting more modern lenses for DSLRs which have smaller sensors). Video lenses for affordable videocams are designed for much smaller sensors, like 1/3". In order to get a reasonable field of view with a small sensor, the video lens focal length has to be very short (for example, Canon XL2 lens is 5.4mm at wide angle). If you put a still camera wide angle lens on a videocam with a mechanical adapter, there is a magnification or cropping effect due to the narrow field of view, and suddenly that 28mm WA lens is now equivalent to a 250mm telephoto.

This is why DOF adapters are used when fitting a still camera lens to a videocam, to avoid having the cropping effect. So one common practice is to use Nikon photo lenses which can fit on both the Nikon still camera and on the videocam DOF adaptor. Other lenses could be used, but some are not so convenient e.g. Canon EOS lenses have no way to adjust the aperture when fitted to a DOF adapter, whereas the older Nikon lenses (non DX) have an aperture ring.

Another couple of points to consider. When you use still camera lenses on a DOF adapter, you normally lose any autofocus functions, so you have to focus manually. Probably there is no IS function either because there is no power to the lens via the DOF adapter.

 

[BMPhoto]

I think maybe you mean video lens rather than film lens? (If I am wrong I apologise.)

Film lenses are very very expensive, and normal people cannot afford to buy them, they will probably rent them when needed.

Video lenses (generally) have motorised zooms that can be used during a shot. Decent video lenses will not breath too much when you adjust the focus.

Still camera zoom lenses, on the other hand, will never be motorised, so the zooming function is used mainly for framing rather than zooming during a shot. Still camera lenses also tend to breathe (i.e. like a slight zoom effect) when you focus, so if you use these for video, a rack focus shot can look a bit strange.

Still camera lenses are normally designed to focus on a 35mm film plane (not counting more modern lenses for DSLRs which have smaller sensors). Video lenses for affordable videocams are designed for much smaller sensors, like 1/3". In order to get a reasonable field of view with a small sensor, the video lens focal length has to be very short (for example, Canon XL2 lens is 5.4mm at wide angle). If you put a still camera wide angle lens on a videocam with a mechanical adapter, there is a magnification or cropping effect due to the narrow field of view, and suddenly that 28mm WA lens is now equivalent to a 250mm telephoto.

This is why DOF adapters are used when fitting a still camera lens to a videocam, to avoid having the cropping effect. So one common practice is to use Nikon photo lenses which can fit on both the Nikon still camera and on the videocam DOF adaptor. Other lenses could be used, but some are not so convenient e.g. Canon EOS lenses have no way to adjust the aperture when fitted to a DOF adapter, whereas the older Nikon lenses (non DX) have an aperture ring.

Another couple of points to consider. When you use still camera lenses on a DOF adapter, you normally lose any autofocus functions, so you have to focus manually. Probably there is no IS function either because there is no power to the lens via the DOF adapter.

Thanks jaegersing, this is a very comprehensive and informative summary on the subject matter. I have benefited from it greatly as I'm also currently looking for a good DOF adaptor. This really helps in concretizing some of the concepts in my mind as I slowly transit from Still photography to videography. Appreciate it.

 

[dannylim]

Thanks... that is comprehensive and some how get myself clearer about the difference... I have seen most of the time when a photographic lens is use on a DOF adaptor, they normally use Nikon lens. I guess those nikon less are more capiatble then the Canon and other lens (Am I right to say so?)

Anyway, thanks again for the info!

 

[jaegersing]

The main point about Nikon lenses is that you can set the aperture manually. If you use a Canon EOS lens it will be stuck at wide open. Great for very shallow depth of field but not very flexible.

If you already have a set of EOS lenses there is a way to work with them though. You can mount the lens on an old Canon camera (very cheap to get these second-hand) to set the aperture, and then just remove the lens without switching off the camera. The aperture will stay at whatever you set and you can then fit the lens to your DOF adapter. Still a bit jialat though, so it's only worth it if you have some expensive EOS lenses that you don't want to buy replacements for. If you are starting from scratch it's better to buy Nikon mount lenses.

 

[BMPhoto]

The main point about Nikon lenses is that you can set the aperture manually. If you use a Canon EOS lens it will be stuck at wide open. Great for very shallow depth of field but not very flexible.

If you already have a set of EOS lenses there is a way to work with them though. You can mount the lens on an old Canon camera (very cheap to get these second-hand) to set the aperture, and then just remove the lens without switching off the camera. The aperture will stay at whatever you set and you can then fit the lens to your DOF adapter. Still a bit jialat though, so it's only worth it if you have some expensive EOS lenses that you don't want to buy replacements for. If you are starting from scratch it's better to buy Nikon mount lenses.

Hi Jaegersing

Glad that I own Nikon Lens at the moment though my video cam is Canon (hmmm... where's my loyalty). I have 2 questions that need your comments:

1) Just curious, I thought the value of DOF adapter is to achieve good DOF, and good DOF is achieved via large aperture. What will be the "flexibility" having to be able to adjust the aperture instead of fixing it at the largest? what are the subtle differences it will make?

2) You mentioned that we can't achieve autofocus with DOF adapter. What then will be a good technique to ensure good focus (on the target subject) is achieved for all the shooting (as I have relied on the autofocus on both my still and video cam all these while)? The video cam LCD is way too small to ensure that, is the external Monitor a must for DOF adapter shooting? Need your experience to advise.

Thanks.

Vincent

 

[dannylim]

The main point about Nikon lenses is that you can set the aperture manually. If you use a Canon EOS lens it will be stuck at wide open. Great for very shallow depth of field but not very flexible.

If you already have a set of EOS lenses there is a way to work with them though. You can mount the lens on an old Canon camera (very cheap to get these second-hand) to set the aperture, and then just remove the lens without switching off the camera. The aperture will stay at whatever you set and you can then fit the lens to your DOF adapter. Still a bit jialat though, so it's only worth it if you have some expensive EOS lenses that you don't want to buy replacements for. If you are starting from scratch it's better to buy Nikon mount lenses.

Hmm... good... seems that i know what lens to buy since i m just starting from scratch... Nikon lens on Canon Body... haha... have the good from both...

 

[thinkvision]

must try Kern and some other french film lens on DRF or DSLR...briliant

 

[cocoa]

must try Kern and some other french film lens on DRF or DSLR...briliant

Quick, show us some "brilant" (btw, just notice there is a spell check function here ) shots taken with Kern and french film lens leh. c'mon don't be shy. no LOL I promise.

 

[jaegersing]

Hi Vincent.

1) Just curious, I thought the value of DOF adapter is to achieve good DOF, and good DOF is achieved via large aperture. What will be the "flexibility" having to be able to adjust the aperture instead of fixing it at the largest? what are the subtle differences it will make?

You need some flexibility because light levels are usually changing. Unless of course you have the luxury of a set with fully controlled lighting.

You also would not want to use max aperture all the time because most lenses will show their defects at full open. Closing down one or 2 stops usually hits the sweet spot, where it's most likely to be sharp edge to edge.

2) You mentioned that we can't achieve autofocus with DOF adapter. What then will be a good technique to ensure good focus (on the target subject) is achieved for all the shooting (as I have relied on the autofocus on both my still and video cam all these while)? The video cam LCD is way too small to ensure that, is the external Monitor a must for DOF adapter shooting? Need your experience to advise.

Ha ha, that is the other drawback to having a narrow depth of field! Yes it is tough to maintain sharp focus. It takes a lot of practice to interpret what is in sharp focus on a small LCD, and outdoors, for example, it can be very difficult indeed. An external monitor is really useful if you are able to lug all this gear around with you. But it's best if it is a high res monitor otherwise you are still half-guessing whether the focus is spot on or not.

Here's a caution about DOF adapters they don't tell you before you buy - fast lenses are not a luxury, they are necessary. I knew that for outdoor shooting I would not have a problem with light loss, since there is plenty of light to begin with. So I thought that the "economy" type f3.5 - f5.6 zooms would be fine. Not so. :thumbsd: Anything from around f4 and slower is likely to show a grainy image overlaid on the video. When the shot is moving and the grain is static, it is really obvious and unacceptable. Some fine-tuning of the adapter is possible to reduce this, but the best solution is simply to use a faster lens, which makes the grain disappear.

Or maybe it is only Brevis that has this problem? Not sure, but my advice is check it out before you buy. See if you can try out a friend's adapter with the type of lens you want to use, and look for any grain or other defects when you stop down the 35mm lens. Pan or tilt the camera with a light coloured background and any static marks should be obvious.

 

[melvinchen]

Major difference in video / photo lens is the image circle size.

Video cameras typically have 1/3, 1/2 or 2/3 inch sensors, ridiculously tiny relative to photography.

As a result, its more difficult to obtain sharpness and resolution, thus much more expensive.

Zoom ratios are far longer than photography lenses, anything between 9x to 100x.

Aperture (in video called iris) typically starts at f/1.8 on the wide end and ends off at f/4 on the telephoto end. This is very impressive given the zoom ratio.

More expensive lenses also have built-in 2x teleconverters which can be flipped-on/off.

There're different grades of lenses, primarily divided into ENG, EFP or HD grade.

ENG lenses start at $2k+ to 10k.
EFP lenses start at 15 to 80k.
HD lenses all start at S$30+k to $100+k.

They all look the same outwardly, but the optical quality are very different.

 

[samvision]

Hi melvin,

awesome comment. Thanks for sharing .

 

[BMPhoto]

Hi Vincent.



You need some flexibility because light levels are usually changing. Unless of course you have the luxury of a set with fully controlled lighting.

You also would not want to use max aperture all the time because most lenses will show their defects at full open. Closing down one or 2 stops usually hits the sweet spot, where it's most likely to be sharp edge to edge.




Ha ha, that is the other drawback to having a narrow depth of field! Yes it is tough to maintain sharp focus. It takes a lot of practice to interpret what is in sharp focus on a small LCD, and outdoors, for example, it can be very difficult indeed. An external monitor is really useful if you are able to lug all this gear around with you. But it's best if it is a high res monitor otherwise you are still half-guessing whether the focus is spot on or not.

Here's a caution about DOF adapters they don't tell you before you buy - fast lenses are not a luxury, they are necessary. I knew that for outdoor shooting I would not have a problem with light loss, since there is plenty of light to begin with. So I thought that the "economy" type f3.5 - f5.6 zooms would be fine. Not so. :thumbsd: Anything from around f4 and slower is likely to show a grainy image overlaid on the video. When the shot is moving and the grain is static, it is really obvious and unacceptable. Some fine-tuning of the adapter is possible to reduce this, but the best solution is simply to use a faster lens, which makes the grain disappear.

Or maybe it is only Brevis that has this problem? Not sure, but my advice is check it out before you buy. See if you can try out a friend's adapter with the type of lens you want to use, and look for any grain or other defects when you stop down the 35mm lens. Pan or tilt the camera with a light coloured background and any static marks should be obvious.

Jaegersing, for your comment and information. i've been looking out for possibility to try one of these with my nikon lens (possibly with my 50mm f1.8 or 50/1.4 planned in the future). However, I've not found any shop carrying Letus, only saw P+S in the market, but I would like to try out Letus first.

Appreciate your sharing.

 

[BMPhoto]

Major difference in video / photo lens is the image circle size.

Video cameras typically have 1/3, 1/2 or 2/3 inch sensors, ridiculously tiny relative to photography.

As a result, its more difficult to obtain sharpness and resolution, thus much more expensive.

Zoom ratios are far longer than photography lenses, anything between 9x to 100x.

Aperture (in video called iris) typically starts at f/1.8 on the wide end and ends off at f/4 on the telephoto end. This is very impressive given the zoom ratio.

More expensive lenses also have built-in 2x teleconverters which can be flipped-on/off.

There're different grades of lenses, primarily divided into ENG, EFP or HD grade.

ENG lenses start at $2k+ to 10k.
EFP lenses start at 15 to 80k.
HD lenses all start at S$30+k to $100+k.

They all look the same outwardly, but the optical quality are very different.

Melvin

Thanks for the sharing, this is good. Do you have some quick info on what does ENG, EFP and HD (High Def????) stands for? I presume that they only fit on the Pro cams and not those Prosumer with fixed lens right. Thanks.