ptz recommendation for film shoot

[zach 0]

Hi All,

 

I'm in the market for a PTZ camera to use for a film shoot and am hoping to get answers to a few (possibly dumb) questions.

 

From looking around, I get the sense that there are two broad categories of cctv cameras. Some (mostly newer models) look like webcams and are often wireless. Others are larger anc take CS lenses. I think I would prefer the latter, as it seems they would have superior image quality (hopefully like an SD camcorder from a few years back?), plus depth of field. However, it seems that those ones require some type of separate mount for the PT part of PTZ and I am having some trouble finding these.

 

Also, I am wondering if either type has limitations on the degree they will pan and tilt. My guess is that they use servos and therefore only have 180 degrees of motion.

 

Anyway, I could use any recommendations for a PTZ camera that would create the most cinematic images possible. I would prefer one that uses the Pelco protocol so I can hack together some custom software to control it. I was thinking something like this: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330370542468&ssPageName=STRK:MEWAX:IT.

 

Thanks,

Zach

[shoreviewsecurity 0]

The camera you link to is not a true PTZ camera in that you will be able to control it via software. Also lens not included and will be shipped from S. Korea. Note the item location.

 

Most if not all PTZ cams on the market will have the Pelco protocol. There are many on the market. It's just a matter of finding one that will meet your "cinematic" needs. Also all PTZ cameras will allow for a full 360 degree rotation and 90 degree tilt. Some also offer a bit more tilt to compensate for horizon on zoom.

 

I guess you will need to find a PTZ with the highest resolution possible but having said, not for the money that ebayer is selling that camera for. Typically a decent PTZ cam could run close to $1000 to acheive your needs. Anything less than that may produce poor results. In this market you get what you pay for.

 

 

Good luck with your search.

 

Mike

[Soundy 1]

Will this camera be used strictly for providing video, or is a prop as well? In other words, does the "look" of the camera matter?

 

In any case, most better "pro-quality" PTZs will do the trick. Pelco has some good models - Spectra if you want a dome (which needs to dangle from something), Esprit if you want something that can sit on top of a pole or platform. The Esprit includes a box housing similar to the EH3512, so a variety of cameras can be mounted inside it as well, giving more flexibility.

 

If you want HD, there are IP-based megapixel PTZ cameras available as well, although those will generally have some slight latency that may or may not be a problem for you.

 

As shoreview notes though, these will not be cheap (I think the Spectras and Esprits run in the $3000-$5000 range), but you really do get what you pay for in this business.

[zach 0]

I'm looking to get something quite inexpensive and was hoping to save by buying older used equipment on eBay. Hd isn't necessary and latency doesn't matter. Ideally, I'd like it to be closer to an SD camcorder than a webcam.

 

I am correct in thinking that the models that take CS lenses will give me depth of field as opposed to fixed lens cameras, correct? Like the difference between a camcorder lens and 16mm film lenses?

 

Are you sure about that model I linked to not allowing software to control zoom and focus? I thought that's why there's a cable going from the lens to body, although that could be just for built-in autofocus.

 

And I doubt that all ptz cameras have 360 degree rotation, as I think many I looked at were 180. By 360 do you mean it can do a full rotation and then reverse, or that it can essentially spin in a circle through several full rotations?

 

Btw, what difference does the dome make? Is it basically like having a wide angle adapter?

[shoreviewsecurity 0]

All traditional PTZ cameras will rotate 360 degress forever until you release the pan button. The wire from the lens is to control the lens iris, etc and not zoom. Although that lens can be manually adjusted, once adjusted, it cannot be readjusted remotely.

 

Depth of view is a function of the lens "mm" value. The larger the number, the more narrow the view will become as you "zoom". For example, a 3.6mm lens will provide a wide angle of view whereas a 16mm lens will narrow that angle. Varifocal lenses will allow for adjustment between its' rated "mm" values from, for example, 3.6mm to 16mm.

[zach 0]

Well, for example the following webcam style ptz cameras from eBay do not have full 360 degree panning:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220502010606&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320427466338&ssPageName=STRK:MEWAX:IT

 

and this small mount does not either:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110297425100&ssPageName=STRK:MEWAX:IT

 

These may not be "traditional" ptz cameras, but they seem to be in abundance at the lower end of the price range.

 

Also, I think you may be wrong about depth of field. It is a function of the ratio of focal length to aperture. Consumer level camcorders, for example, generally have sensors that are two small to achieve a shallow depth of field. This is why people use adapters to put 35mm lenses on their camcorders.

 

Basically, I highly doubt any of the ptz cameras with a fixed lens would allow shallow depth of field, but I was hoping the ones that take CS lenses would, since those are basically the same as 16mm film lenses.

 

But now the question is, are there any CS lenses that allow software controlled zoom and focus?

[Soundy 1]

I am correct in thinking that the models that take CS lenses will give me depth of field as opposed to fixed lens cameras, correct? Like the difference between a camcorder lens and 16mm film lenses?

 

Not exactly. CS refers only to the specific mount design (diameter, thread, etc.). CS mounts can have fixed-focal-length or varifocal lenses attached.

 

Depth of field refers to the area, front-to-back in a view, that remains in-focus. It's affected by both aperture and focal length - a very short focal length will give you near-infinite DOF (meaning everything from very close, back to the far distance, will be in focus) but give a very wide view with little detail. Long lenses will get you a narrow field of view and give you more detail on distant objects, but the focus will become a lot trickier.

 

There's some more info, along with some examples, here: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

 

Are you sure about that model I linked to not allowing software to control zoom and focus? I thought that's why there's a cable going from the lens to body, although that could be just for built-in autofocus.

 

Nothing in the ad you linked to suggests that camera supports remote-controlled zoom OR autofocus. The wire you're referring to is likely the wire for the auto-iris drive, that allows the camera to adjust the lens iris in response to changing light conditions. The two small silver knobs you see on the bottom of the lens would be the zoom and focus adjustments.

 

And I doubt that all ptz cameras have 360 degree rotation, as I think many I looked at were 180. By 360 do you mean it can do a full rotation and then reverse, or that it can essentially spin in a circle through several full rotations?

 

If what you looked at were mostly webcams, then yes, those would generally be limited to 180 degrees or less - they'd have little need to go beyond that. CCTV PTZ cameras almost exclusively have 360-degree rotation - as shoreview says, push to controller to one side, and the camera just goes around and around until you release the control.

 

Btw, what difference does the dome make? Is it basically like having a wide angle adapter?

 

Just different styles. The dome provides protection for the camera mechanism, often as part of a sealed environmental housing. Dome PTZs tend to be more compact, because the camera itself is designed specifically to fit inside a dome. The "bubble" itself is usually a smoked plastic, so others can't see where the camera is pointing.

 

The reason I asked if it mattered was mainly for cosmetics: if this camera was supposed to actually appear in your film, something like the Esprit would probably be more "telegenic", as people would be able to see it moving and aiming in different directions, thus reinforcing the image of it being a PTZ. In a typical dome PTZ, as described above, the camera itself isn't usually directly visible, so there would be no indication to viewers that the camera is looking around in different directions.

[Soundy 1]

Also, I think you may be wrong about depth of field. It is a function of the ratio of focal length to aperture. Consumer level camcorders, for example, generally have sensors that are two small to achieve a shallow depth of field. This is why people use adapters to put 35mm lenses on their camcorders.

 

Basically, I highly doubt any of the ptz cameras with a fixed lens would allow shallow depth of field, but I was hoping the ones that take CS lenses would, since those are basically the same as 16mm film lenses.

 

The limited DOF in this cameras is not because of the lens mount, and not DIRECTLY because of the sensor size. The problem is, with the smaller sensor, you need to use shorter lenses, and THAT is why you get greater DOF. Typically CCTV cameras have 1/4" or 1/3" sensors, compared to 16mm frame sizes in film, or 24-35mm sensors in DSLR cameras.

 

For example, my 50mm f/1.8 lens on my Canon 40D ("1.6x crop" APS-C sized sensor), I get about a 25x17-degree field of view and very shallow DOF at f/1.8. To get that same FOV on a 1/4" CCTV sensor, you'd use an 8mm lens... and 8mm will give you pretty substantial DOF no matter what you do (well, unless you can get your aperture down to f/0.2 or so - good luck with that).

 

But now the question is, are there any CS lenses that allow software controlled zoom and focus?

 

None that I'm aware of. Generally, the camera and lens for this purpose are a single unit. You'd need some way to power the lens and feed it control signal separate from the camera. Frankly, if you do find something like that, it's likely to be fairly expensive.

[zach 0]

Thanks, Soundy. I think you're basically saying that I can kiss shallow depth of field goodbye and should probably just go with a "webcam style" IP camera. I was confused because CS are 16mm size lenses, while I believe 16mm is equivalent to a 2/3 sensor, not the 1/3 I see on the best cctv cameras. I thought maybe they had some type of built-in adapter.

 

That said, do you have any inexpensive recommendations? The look of the camera itself does not matter.