Is there anything special about a "megapixel" lens?

[videotiger 0]

I am looking for a motorized zoom lens for a StarDot C/CS mount 5 megapixel IP camera.

 

The camera's spec' include a description of the imaging sensor as being 1/2.5" (whatever "1/2.5" means, maybe by doing the math, 0.4"???). The lens that came with the camera is marked as being for 1/2" format.

 

In hunting around, the number of motorized zoom lenses for 1/2" format are limited, even moreso for those labelled "megapixel".

 

So my question is: Will a lens for 1/2" format do the job, or will there be a substantial benefit in getting one labelled as being for "megapixel" use?

 

Also: I would like the camera to be controlling the iris on the lens via the iris control output. Am I looking for a lens with a "motorized iris", or one with a "DC auto iris"? Having trouble with the terminology--it's not always clear.

 

Thank you in advance!

[survtech 0]

Megapixel lenses are designed to tighter tolerances than standard lenses to be able to focus better over the entire image. You can use standard lenses on megapixel cameras but the results may be less than optimal. That said, I am unable to find any megapixel zoom lenses so you would have to use a standard zoom lens. One thing to consider is that a 1/2" lens designed for a 4:3 imager may exhibit some "tunnel effect" when used on a 16:9 megapixel camera. Keep that in mind when ordering lenses. You may want to get lenses designed for 2/3" cameras.

 

There are plenty of auto-iris megapixel lenses, however.

[Soundy 1]

Your average CCTV lens uses relatively low-quality optics and won't create a terribly sharp image. With basic low-res analog cameras, this isn't a problem because it's still sharper than the sensor can detect.

 

With megapixel cameras, such softness becomes noticeable... more noticeable as the resolution increases. So "megapixel" lenses are designed to provide sharper, clearer images - the common term is "resolving power" (loosely analogous to resolution in a sensor). You'll also find they're rated in "megapixels" - although they don't "have resolution" as such, again, the higher the camera resolution, the higher quality lens is required for optimal results - a "2MP" lens, for example, would look softer on your 5MP camera, than the proper "5MP" or higher lens.

 

So while a standard lens will work, you may not be overly happy with the results, especially if you compare them to the included lens.

 

The camera's spec' include a description of the imaging sensor as being 1/2.5" (whatever "1/2.5" means, maybe by doing the math, 0.4"???). The lens that came with the camera is marked as being for 1/2" format.

That will work fine - that is a description of the imager size, usually as a fraction in inches.

 

I would like the camera to be controlling the iris on the lens via the iris control output. Am I looking for a lens with a "motorized iris", or one with a "DC auto iris"? Having trouble with the terminology--it's not always clear.

There are two types of "motorized iris" lenses - "DC drive" is the most common, where the camera itself controls the iris by varying the DC voltage fed to it... some older systems used a "video iris" type lens, where the camera only provides power, and a light sensor within the lens controls the iris. These aren't so common anymore, though, and some newer cameras may not support this option.

[hardwired 0]

Stardot cameras use a DC auto iris lens.

 

I did find Fujinon zoom megapixel lenses rated for up to 1.3 megapixel, that would at least be better than standard resolution lenses, and Fujinon lenses have seemed to be better than most, in my opinion... However, they seem to retail at nearly $5000 USD.

 

You might want to consider a camera with an integrated zoom lens, such as the Sanyo VCC-HD4000 4 megapixel, with a 6-63MM zoom range, or the Avigilon 2MP camera with a 5-85MM zoom range.

 

What zoom range are you looking for? Another option to consider might be to get the camera closer to the subject, if possible, and use a wireless bridge back to your viewing/recording location.

[videotiger 0]

Thank you for all of the information and suggestions!

 

I've seen the Fujinon as well as Computar lenses. The max focal length/zoom is something I need to decide upon. I checked today and the image sensor is 4:3 format.

 

This camera will replace an NTSC 600 line camera I installed on a house in Honolulu. The house is located up one of the mountain ranges and has a nice scenic view, so I would like the camera to be able to pan/tilt/zoom. Besides being able to pan it around for security at the house, I would also like to be able to use it take in the view. Things range from 1/2 mile away to about 15 miles, but most interesting things will be about, at most, five to seven miles away.

 

I did come across a Computar lens with some incredible max focal length of like 750 mm, and a fog filter, but it cost as much as my first car!

[Korgoth Of Barbaria 0]

Try searching ACTi knowledge base, there is some article about megapixel vs standard lenses.

 

Also the best part in lens is middle part. So if you have 1/3" sensor camera, You will get better image on 1/2" lenses than on 1/3".

 

We use EVETAR lenses, not expensive and rly good.

I was making comparison with pentax lenses, and pentax was like 7% better but 2x more expensive.

[videotiger 0]

Thank you for the recommendations!

 

I've come across Kowa, which has some potentially viable lenses. I looked at one and got sticker shock though--like in the $1800 range. This is a personal setup, not a commercial, so cost is a factor.

 

I determined that the pan/tilt mount I have only puts out a single zoom control signal (besides the common). Yeah, there's a reason the mount was relatively inexpensive, I'm learning. I noticed that zoom controls usually have four wires (zoom motor control and a brake coil pair). Is there a standalone RS485-based Pelco-D protocol controller that has a four-wire zoom output?

[NotoriousBRK 0]

Why does the zoom need to be motorized?

 

There are very very few lens manufacturers that do motorized zoom lenses right now, and those that do are mostly intending it for backfocus adjustment (eg: very very infrequent changes) and not as a quasi-PTZ setup.

 

For a 5 MP camera you're going to be looking for a lens with probably a 250 lp/mm or better rating. You're going to have a hard enough time finding that, much less with motorized zoom.

[thewireguys 3]

Spacecom Andromeda 1/2" 20-700mm Motorized 3.6MP Lens

[Soundy 1]

^Do I even want to know how much that bad boy costs???

[thewireguys 3]

^^^ nope

 

http://www.spacecom.co.jp/en_product/D_motorized_zoom_lens/index.html

[survtech 0]

The HZ20700R ?HZ20700RDC?HZ20700RAI might do. Its 700mm max zoom focal length would see an approximately 240-foot-wide swath at 5 miles with a 1/2" sensor. Of course, at that zoom level, the camera would have to be mounted with extreme care to prevent any movement. Even an infinitesimal movement of the camera would cause extreme "jitter" in the picture!

 

You can also forget about any affordable pan/tilt mechanism for that amount of zoom - too much "slop" in off-the-shelf mechanisms.

 

If cost is no object (and I know it is), you could use something like this:

 

NB Security Systems PTZ-7000SS Stainless steel long range PTZ camera.

 

* Custom built IP66 SUS316 stainless steel long range PTZ camera system.

* Endless rotation and variable speed from 0,1° to 7°

* Built-in RS485 Pelco D controller and high accuracy of Pan and Tilt

* Multiple options, Auto focus, washer, wiper, heating ...

 

"The PTZ-7000SS long range PTZ camera system is custom built to every customer, to meet the application specifications. The basic setup of the ptz system is built around very high level components like:

 

Pan tilt:

The IP66 pan tilt with built-in RS485 Pelco D controller is a heavy duty step motor pan tilt. The pan run 360° endless rotation with built-in sliprings to transfeer the signals. The pan/tilt has variable speed from 0,1° to 7° and a very high accuracy of pan and tilt.

 

Housing:

The very large IP66 housing made of stainless steel can house the largest motorized lenses up to 1500mm. The housing can be equipped with Wiper, Washer, Heater with fan, circulation fan and other options.

 

Lens:

The PTZ system can be ordered with 60X zoom 12,5-750mm with motorized 2X extender (25-1500mm), X55 zoom 10-550mm zoom with motorized 2X extender (20-1100mm), X50 zoom 20-1000mm or other large zoom lenses of your choice. Some lenses can run auto focus.

 

Camera:

The normally used camera is a very high sensitive 1/2" Exview ccd camera. For applications where extreme sensitivity is needed a EMCCD camera can be installed."

 

http://www.2bsecurity.com/PTZ-7000SS-stainless-steel-long-range-ptz-camera.html

[thewireguys 3]

Since we are throwing the price out the window check out Rvision.

 

 

http://www.rvisionusa.com/product_clg.html

[Guest]

^^^ nope

 

http://www.spacecom.co.jp/en_product/D_motorized_zoom_lens/index.html

 

The new Pentax lens range can be specified with their PAIR2 option offering

 

Focal Length 12 - 1,680mm

Reduction of Heat Haze

Integrated Electronic Image Stabilizer

Reduction of Airborne Interference, e. g. Fog, Rain, Sand, Smoke, Snow

Autofocus

RS232C Interface

 

Needs a big housing and PT head though.

 

Ilkie

[videotiger 0]

That stainless steel camera looks like it belongs in a kitchen

 

Based on the view I'm getting with the existing bullet camera, which I set its varifocal lense to full-zoom (aka 9.5 mm), I suspect that I don't need anything more than 80 - 100 mm. The comment about a longer focal length lense requiring a rock-steady camera mount is something I didn't take into consideration.

 

Thank you for all of the leads and suggestions. The search (and savings) goes on.