f1.3, f 1.0 f1.4... how do these factor into picking a lens

[CSCOUT2001 0]

I am after knowledge and soaking up what I can

 

Due to a previous question I had, I am curious as to how these numbers play into picking a lens. Can someone lead me to a sight so I can read about it or can you describe them here?

 

thanks

[CSG 0]

F 1.0 is a fast lens, and admits more light. The F stop is a logarithmic number, therefore each increment can produce a substantial difference, such as F1.4 is a lot worse in admiting light than a F1.2, and F1.0 is best. Generally, the cheaper the lens, or the wide the focal range, the slower the lens. You can always talk to a film camera enthusiast for more understanding of lens, and F stops. For CCTV purposes you want the lowest F-stop, and a 3x8mm F1.0 is my standard choice for most applications.

[Cooperman 0]

It's also worth bearing in mind that the wider the aperture (i.e. the smaller the 'f' stop), then the lower the lens resolution will be.

 

This will be particularly noticeable in terms of 'edge' resolution.

[kandcorp 0]

Agreed. I currently have been playing around with all sorts of lenses. I am really trying to find the best for our camera line. It seems when indoor F1.2-F1.4 work decent. But when your talking about an outdoor application we have found, at least with our cams, the Day/Night F1.0 not only looks the best during the day and night, it focuses the best. Using the F1.4 outdoor, especially at full WIDE, would not focus right outdoor. Oh and of course the quality/price of the lens makes a huge difference.

[jkbrowne 0]

I have an inexpensive day/night camera (no mechanical cut filter). If I were to replace my F1.4 lens with an F1.0 would the night sensitivity be improved since this lens lets in more light?

[jisaac 0]

you do have to take in consideration your application. there is a place for the 1.4 lens also. Granted we use them rarily they can be usefull in a situation that has very bright parts of the day in which your luminance level can be an extremely large amount. Putting in a 1.4 can help with your image getting to bright. Usually you can predict that in designing the system but sometimes you did not know about a certain time of the day that creates a problem.

But in general the 1.0 and similar are your best bet. The day/nigth lens have exceptional performance with little shift of focus from night to day. The back focus is pretty easy to do with those.

kandcorp,

if you use a neutral density filter when setting up your camera you will get better performance out of any lens inside or outside.

 

 

and yes your change in lenses will improve your night sensitivity.

I would highly recommend the fujinon d/n aspherical lens. The are extremely easy to adjust. Back focus ring is easy to get your fingers around and manuevor. plus they are not that expensive. pretty cheap if you ask me.

[rory 0]

I have an inexpensive day/night camera (no mechanical cut filter). If I were to replace my F1.4 lens with an F1.0 would the night sensitivity be improved since this lens lets in more light?

 

It still depends on the camera, whether it can handle that extra light, and what it does with it, cheap cameras cant typically handle light efficiently ..

 

Do you have the specs on the camera?

I mean its worth a try anyway.

 

BTW Fujinon Day Night Lenses are said to be very good. But for a camera without a mechanical I Cut Filter, you dont need a day night lens, just get an aspherical lens

[jisaac 0]

the fujinon aspherical lens is a day night. they dont make on thats not.

[rory 0]

True, i must have been thinking of Tamron

 

Fujinon's F:0.95 lens is also great for Exview Color Cameras ... sees in almost no light .. but you do get that noise effect at really low levels.

[jisaac 0]

here is an example of a fujinon day/night lens that was put on a cheap cheap cheap camera that was suppose to be a temporary camera for the weekend. this camera right here is an old mace cam 37 (kandcorp and matt remember those). These were retailing for about 110 about 2 years ago.

 

 

 

notice not much shift in focus even though the light level around the whole room drastically reduced. so those lens do make the cheap cameras look decent. although they do catch a glare pretty easy. anyone notice that?

[CSG 0]

I got some Ademco 3x8 f.10 lens, (I think they might be relabeled Fuji). Anyhow, I like the feature where you can adjust the focus or zoom independent of the locking screws. On Tamaron lens, after you focus it can be tricky to lock down the screws without messing up the focus setting, especially while hanging off a ladder!