why does my 30x ptz seem only like 10x?

[james99]

I bought this camera:

Built-in POE HD 5MP Outdoor IP Camera 30X Zoom Waterproof PTZ Speed Dome Camera | eBay

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I installed it and it seems to be ok using ptz controls from my 6 year old Dahua nvr. Using a poe+ switch that gives enough power for it.

But, when I zoom in on a distance, I know for a fact (based on years of previously using a 10x ptz) that the max zoom this camera is giving is only 10x, since it compares exactly to my old ptz.

I am wondering why I cannot get the max 30x zoom from this thing? Even using their webpage interface, no joy in getting the "30x" zoom. Is this a common deal when buying these inexpensive cameras? It's too cheap to return, so I can live with it with only 10x, but I really would like some insight. I have messaged the seller, but don't really expect an answer as it is a chinese camera. Thanks.

 

[Kameraad]

It's 4.3mm - 129mm, so that's 30x..

 

[SouthernYankee]

Its is from EBAY, You actually believe the write up ? It has two reviews. It is Chinese junk. Send it back .

 

[Ssayer]

A quick search just using it's MPN and I see that they're lying. I immediately found it on Amazon. There it is shown as 20x Optical and 10x Digital. Now... figure that they're even lying on Amazon (there are no reviews), and you sort of get why you see what you see...

 

[james99]

well, I really am thankful all for the quick replies. It was so cheap that I am going to keep it. one of these days, when I have enough $$$ I will order a real 30x ptz. you guys are right of course....and I thank you for that. sigh...when will I learn? If it's too good to be true.......

 

[bp2008]

When they say "30x", that only describes the difference between the widest view and the narrowest view. You could have a lens with a zoom range from 3mm to 90mm and call it 30x, or a zoom range from 6mm to 180mm and also call it 30x.

One way you could try to verify if you're getting 30x is to zoom in as far as it will go on a distinctive object, save a snapshot, and then zoom out as far as it will go and save another snapshot. Then in an image editor like GIMP or Photoshop, rescale the zoomed-in photo's dimensions to 1/30th their original size (e.g. 1920x1080 -> 64x36), copy and paste the resulting (very small) image over the zoomed-out photo and it should line up nearly perfectly.