Zoom Lense

[Crazy Horse]

Hey guys!

I was wondering if anyone could point me in the right direction.

I have a Canon a85 and enjoy taking picture of wild life along the coast. There has been many many times where my 3x zoom lense on my camera just isn't close to enough.

I was wondering if anyone could point me in the right direction for a good zooming lense.

Also, what exactly does a 300mm (for an example) lense mean? Is it just a more power zoom lense than a 16mm lense on my Canon A85?

Thanks a million guys.

[cactusclay]

Zoom means a lens can go from one focal length to another, for instance a 24-70 zoom would go from wide angle to the short telephoto range. A 300 mm lens would be considered a long telephoto. The higher the number the more magnification the smaller the number the wider the view that is taken in.

[Crazy Horse]

Ah, ok cool.

So my 3x zoom = 16.2mm?

What would a 300mm lense equal?

Do you have any recommendations on a lense?

[Crazy Horse]

Is this (http://www.camera-warehouse.ca/Product.asp?pr=TC-DC52) Lense good?

It is a 2.4x lense. Since I have a 3x on the camera, will that equal 7.4x zoom?

Thanks a lot guys!

[Geeeyejo]

You are limited on your options with the A85. I believe that they may make a tele convertor to possibly double your 3x to 6x. It would attach to the front of you lens I believe. That is one reason why many upgrade to a DSLR with interchangeable lenses. You attach/remove the appropraite lens for the situation. Not possible with the A85 as the lens is not removeable.

My S1 has a 10x zoom that is supposed to be the equivalent of a 380mm lens for a 35 mm camera (it is actually less but digitals with a smaller sensor than the size of a 35mm frame use a conversion factor - for example it is x1.6 for my 10D - a 50mm lens is like a 80mm. You can also crop your finished pics with software to make the final image appear larger as well.

[Crazy Horse]

Thank you for that quick and informative reply.

What about if I go with a 3rd party lense like this beast?

http://www.bugeyedigital.com/product_main/bow-aub37a60.html

and

http://www.bugeyedigital.com/product_main/ckc-cvs8.html

[Geeeyejo]

Looks pretty cool - but added to the A85 - could have bought an S1 cheaper! Haven't had experience with these but looks like an option!

[eastcoast909]

Ok, I'll try to answer some of this.

Your A85 has a 5.4 to 16.2 mm lens (actual size). From the shortest length 5.4 mm to the longest lenght 16.2 mm the lens will zoom 3 times (16.2/5.4).

If you had a comparable set up on a 35mm camera this would roughly equate to a 35mm to 105mm lens (taking into account the sensor difference)(according to the specifications from Canon). If you want to know more about sensor size relating to apparant lens size check out the sticky section in the EOS section at this link,

http://photography-on-the.net/forum/showthread.php?t=45388

So what does this mean? Here's a link to a nice calculator that will let you determine approximately what size lens you would need to take an image that will occupy the full size of you sensor at different distances. Just type in the size of object and the distance away and it will give you the size of lens needed to magnify the object to that size.

http://www.photo.net/making-photographs/lens

For example if you wanted to take a picture of a 5 ft. person that is 15 feet away, and have them fill the frame then you would need a lens of 112mm on a 35mm camera.

So, your camera will give you an equivelent magnification of a 105mm lens.
With the teleconvertor you mention you can increase that to 70 to 210mm. You will lose an f stop doing so and possibly some sharpness.

The CrystalVue lens shown is not a teleconvertor. It is actually a monocular. It has to be focused before it can be used in front of you existing lens.

I have this lens and used it with my S45 with varying degrees of success. It does work, but there are several caveats.

You lose one if not two f stops so you need a good deal of light.

You become more susceptible to camera shake when you start to zoom out to the higher magnifications. You really should put it on a tripod to stablize it, or at least a stable surface.

It is very slow to set up.

I found that I had the best success when I unmounted the CrystalVue,

focused it on the object of interest,
attached it back to the camera,
zoomed the camera in to the desired magnification.

This takes a long time so you're not going to use it for long distance action shots.


It has a fair bit of chromatic abberation and does cause vignetting at some zoom aspects.

The upside is that it does give you a large amount of magnification.

The apparant lens size attached to you A85 would be 280 to 840 mm.

I'm not saying don't get it, I'm just saying that you should be aware of its limitations. I found that I went to a DSLR partially because of some of the issues I had with the lens llimitations on the S45.

This lens and adapter is also available through www.ckcpower.com (http://www.ckcpower.com/)

Their site is under upgrade you might have to send them an e-mail to determine exactly what you need to attached the Crystal Vue lens to your camera. It will require at least one adapter in addition to the lens.

hope this helps,