Question about camera linses

[m00n]

I bought a digital camera from a friend a few years ago. It came with three separate lens'. I have no clue what they are used for and when I would want to use them or how... I know some of you guys are camera buffs and what not so I was hoping to get some help.

Lens 1) Vision Optics Titanium 0.48X Digital Wide Lens.

Lens 2) Vision Optics Titanium 2.0X Digital Tele Lens.

Lens 3) Olympus 0.8X Wide Conversion Lense.

As you can see, they are three different types. When would I use them and for what?

[sputnik]

They all convert the focal length of the lens on your camera by the

number indicated. Lens 2 doubles the focal length (higher power

telephoto). The other shorten the focal length byu the given

factor and give you a wider angle. These lenses should screw into

the filter threads on the camera lens. I've never heard of Vision

Optics. If you use these, you may notice chromatic aberration or

color fringing around the edges of objects in the photo.

[m00n]

Sputnik, I don't mean to sound like a moron, but can you put that into terms that a 1st grader could understand?

[sputnik]

I'm just guessing, but if you got this as a used camera a couple of

years ago, it may have a fixed focal length (no zoom) or may have a

very limited

zoom range. Those three converters are a quick fix to allow for

wide angle and telephoto shots. Some

are very good but lower quality brands can degrade the image

quality. Chromatic aberration happens when the lens optics don't

quite refract the different wavelengths of light the same way and the

light splits into different colors like in a prism. You can get

slight color fringing

that muddy's up the picture. Basically, adding those converters

will lower the quality of the image to varying degrees but give you the

flexibility to get wide angle and telephoto capability. I'll

guess that the Olympus

converter isn't too bad but the others might be of lower quality.

But if you need to go for a wide angle shot and can't physically back

up, then attaching the wide angle converter is better than missing the

shot. I think that telephoto converters perform better than wide

angle converters but I'm not sure. Just play with them and see

what results you get. Film is cheap with a digital camera.

[sputnik]

Do the converters thread onto the camera lens?

[m00n]

Yes, the converters are threaded.

[LarryC]

Lens 1) Vision Optics Titanium 0.48X Digital Wide Lens.

Lens 2) Vision Optics Titanium 2.0X Digital Tele Lens.

Lens 3) Olympus 0.8X Wide Conversion Lense.

...When would I use them and for what?

Sput is right, of course, in all that he says. Is the camera itself an Olympus? I'm sure that conversion lenses have to be brand-specific, in order to keep the optics straight. If it's not, I doubt you can use them.

Sput was asking if the extra lenses actually screw into the end of the lens built into the camera, which would have matching threads at the end of its own lens. Again, if they don't, you can't use them.

Vision Optics makes night vision thingies for the military, and I'd think that's where those are supposed to go. I didn't see anything on their website saying they're made for cameras.

As for what they do: less than 1.00 would widen the field of view, i.e., make the lens more wide-angle. This means that the field is wider, but that objects become smaller, especially in the distance. There are pros and cons to using this type of lens. It's generally unflattering for people pictures, but good for wide-angle Western scenics. Great for your local scenery! 0.8X is a moderate widening of your existing lens, while 0.48 is rather extreme.

Over 1.00 would be more telephoto, i.e, the field is narrowed, magnified, and brought closer in ( just like higher-powered binoculars!). 2.0X doubles all those figures -- things are twice sized.

Some mind-numbing figures for ya -- if the camera's lens is a zoom, it would zoom between mild wide-angle and mild telephoto. For example, a focal length range of 7mm - 21mm in a compact camera would be equivalent to, say, 28mm (wide-angle) to 85 mm (telephoto) in a 35 mm camera. 50mm is "normal angle," i.e., the pics look like we'd see things. These numbers are usually written on the far end of the lens, or close to the lens. If there is just ONE mm-number, it is not a zoom.

So, a 0.8X lens would reduce those to 5.6 mm to 17 mm, equivalent to 22 to 70 on a 35 mm camera, which is between wider wide-angle and a lesser telephoto.

A 2.0X converter would double the focal lengths to 14mm to 42mm, or 56mm to 170mm on a 35mm camera. These are very long lengths for a compact camera, and you might have problems with camera movement blurring your pictures. You might need a tripod.

If your camera has a zoom (a range between two focal-length numbers), you probably won't need the conversion lenses. Note: use the telephoto end of the zoom to take pics of people.

If it only has one mm-number, all 3 conversion lenses might be useful, although the 0.48X would probably be too wide to be practical for you.

If you camera has a display screen on the back, you can check out what each of these does for you, and where you should use them.

Larry

[Speedball]

Staying in one place, try each of the lenses and see the difference between them.

[Jay481985]

I'm just guessing, but if you got this as a used camera a couple of

years ago, it may have a fixed focal length (no zoom) or may have a

very limited

zoom range. Those three converters are a quick fix to allow for

wide angle and telephoto shots. Some

are very good but lower quality brands can degrade the image

quality. Chromatic aberration happens when the lens optics don't

quite refract the different wavelengths of light the same way and the

light splits into different colors like in a prism. You can get

slight color fringing

that muddy's up the picture.

To further help out on chromatic abberation, when you have a high

enough len, it does act like a lense, that is why most high end junior

telescope are mirror and all nasa grade telescopes are mirrors. The

high power lenses do act as a prism, you still see what you want but

the colors are a psychadelic state. Also the idea of using mirrors was

proposed by Newton.

There also some tricks for lenses too... there is background distant

distortion, I forgot the real name its been awhile. Just when you use a

high powered telephoto lense the background appears closer to the

subject than if you used a wide angle it appears further away. Sorta

like the "objects in mirror may seem closer than they appear" on

mirrors.

[WMcD]

I have a little old Sony Mavica. One of the family which has a floppy drive. Good enough for internet postings. It has threaded fittings at the nose of the lens. It also has zoom. Sort of mild telephoto and mild wide angle.

Video recording camera have the same set up.

The add on lenses are typically used for them to give more telephoto and more wide. The numbers tell the relative effects. So the add ons can be used on both digital "one picture" and motion picture types.

- - - -

I grimmace that most of the old point and shoot Instamatic types had a wide angle lense. Of course there is a logic to it. Many shots were "Let's get a picture of the family on the couch at Christmas." What, there is no light? The built in flash will do the job. Most results are horrid even if everyone is in the final print.

= = = =

I have used the add on wide angle type on the Mavica. That was when taking shots of the condo I eventually bought. This was good because it took in more of the room and furnature.

- - -

Too bad Colter is not here. He could give us some insights. For example. Most shots of models you see in magazines are made with telephoto lenses from the other side of the room. They are very distinctive and different from the point and shoot wide angle.

= = = =

A worst case would be if the camera was a nose lenght away from the human. The nose tip would be big and the eyes would be twice as far away, thus smaller in the view. Ears would be even farther away, and smaller. So the distortion is simply a matter of distance.

We can change that by moving the camera point of view back. If we're 10 feet back, the nose is 10 feet and the eyes are 10 feet and 1 inch. the ears at 10 feet and 2 inches Now there no (or less) distortion from the distance.

But the human overall is small in the view. What to do? We need a telephoto lense to make the human fill the field.

= = =

Much of this is that our eye - brain combination compensate for distance. E.g. if we are close to a person, the nose is not seen as bigger because it is close. The ears are not seen as smaller because they are more distant. But that does happen with camera lenses and the image which is put down on film or the sensor chip.

- - -

Gil

[sputnik]

......A worst case would be if the camera was a nose lenght

away from the human. The nose tip would be big and the eyes would

be twice as far away, thus smaller in the view. Ears would

be even farther away, and smaller. So the distortion is

simply a matter of distance....

Gil

Not a good case for dogs either.