Omega Owners Forum

Chat Area => General Discussion Area => Topic started by: waspy on 14 October 2009, 20:58:25

Title: Camera Lens's
Post by: waspy on 14 October 2009, 20:58:25
Can you give me some info on camera lens's for me please?
What's meant by 75-210mm & 100-300mm :-/

What price could i expect to pay for one that fits an Olympus OM10 fitment? I've looked on ebay, but i'm unsure what i'm looking at :-?
I don't want to pay much as it's for my NV monocular

They're not my specialist subject :-[

Thank you
Title: Re: Camera Lens's
Post by: Mr Skrunts on 14 October 2009, 21:23:34
Technically I dont know the jargon.

But a simplistic way to try and explain is to  (Theorecally) convert the mm into metres.

So the 75-210 will focus best from a distance of 75 to 210 metres away

and the 100-300  will foces best from 100 to 300 metres.

yes you will see imsges outside the 2 ranges.  but the bigger the lens 210/300 the further distance it will see.(in effect bring the object closer.

so 100 / 150 /300 you can still see the same object, but 300mm it may fill the screen, so for example all you will see is the tree in a park, 150 you will see the 1st tree and say 5 tree's either side of it, at 100 you might add annother 10/20 either side of the original image.
Title: Re: Camera Lens's
Post by: waspy on 14 October 2009, 21:28:30
Thank you Mr Skruntie :y
Title: Re: Camera Lens's
Post by: Mr Skrunts on 14 October 2009, 21:52:08
http://www.fuji.co.uk/consumer/digital/digital-cameras/d-slr-long-zoom/finepix-s1000fd-119757/Design

Scroll down to the bit about 12x optical zoom.  Only posting the link to show you the 4 pictures.

but shows its lowest zoom to its max.  wide / 3x /5x and 12x
Title: Re: Camera Lens's
Post by: waspy on 14 October 2009, 22:00:12
Quote
http://www.fuji.co.uk/consumer/digital/digital-cameras/d-slr-long-zoom/finepix-s1000fd-119757/Design

Scroll down to the bit about 12x optical zoom.  Only posting the link to show you the 4 pictures.

but shows its lowest zoom to its max.  wide / 3x /5x and 12x


Uhm thanks. I knew what the X3, X5 etc meant, it was the mm that made me wonder.
Title: Re: Camera Lens's
Post by: Kevin Wood on 14 October 2009, 22:33:56
The value in millimetres is the focal length (effectively the magnification). http://en.wikipedia.org/wiki/Focal_length.

Where there's a range of focal lengths it's a zoom lens that is continuously variable between the two extremes.

The other parameter of interest is the maximum aperture or f number (e.g f2.8) which relates to the maximum amount of light it will collect (the "brightness" of the image).http://en.wikipedia.org/wiki/F-number

You should be able to find some bargains on ebay. Film equipment goes for pennies these days.

I'm not aware of the mount that the OM10 had but I've got a couple of old lenses with a 42mm pentax screw mount if you want to experiment.

Kevin
Title: Re: Camera Lens's
Post by: Mr Skrunts on 14 October 2009, 22:39:23
Quote
The value in millimetres is the focal length (effectively the magnification). http://en.wikipedia.org/wiki/Focal_length.

Where there's a range of focal lengths it's a zoom lens that is continuously variable between the two extremes.

The other parameter of interest is the maximum aperture or f number (e.g f2.8) which relates to the maximum amount of light it will collect (the "brightness" of the image).http://en.wikipedia.org/wiki/F-number

You should be able to find some bargains on ebay. Film equipment goes for pennies these days.

I'm not aware of the mount that the OM10 had but I've got a couple of old lenses with a 42mm pentax screw mount if you want to experiment.

Kevin

Allways wanted to understand the F settings, took one look at the link and reakised the "Auto" setting on my camera is fine.  :y :y
Title: Re: Camera Lens's
Post by: albitz on 14 October 2009, 22:43:15
All I know is ,the lower the F number the better,and more expensive. :y
Title: Re: Camera Lens's
Post by: Kevin Wood on 14 October 2009, 22:45:22
Quote
Allways wanted to understand the F settings, took one look at the link and reakised the "Auto" setting on my camera is fine.  :y :y

Go on - take it off auto and have a play. It'll improve your photography. And I know you appreciate good photography. Or is it more the boobs subject matter?  ;D

Kevin

Kevin
Title: Re: Camera Lens's
Post by: Mr Skrunts on 14 October 2009, 22:45:46
Quote
All I know is ,the lower the F number the better,and more expensive. :y

Sounds about right.


Title: Re: Camera Lens's
Post by: Ian_D on 15 October 2009, 00:35:09
Quote
All I know is ,the lower the F number the better,and more expensive. :y
Basicly, the lower the F number, the 'faster' the lens is.

If you were to take a photo in low light, and didn't use a flash you would need either a tripod or a fast lens.  ::)

I've just bought a lens from my camera that has an f1.4, which as far as I know is the fastest I can buy for my camera. 8-)

The F number is the size of the aperture, so the bigger the aperture, the more light it lets in, and therefore the faster the camera can capture the image (ie faster shutter speed = sharper image). Remember that the smaller the F number, the bigger the aperture. So 1.4f = Very Big, and 22f = very small.

Again this isn't too much of a problem if you were taking photos of buildings with a tripod, but lets say you were taking a photo of a moving car in low light. With a normal lens, it would be blurred.

The other point to mention is that the smaller the F number, the smaller the FOD (field of depth) is. This can be used to create some fantastic effects, however at the same time can make focusing on subjects difficult. :(

What lenses do you currently have?
And what do you intend to take photos of?
Title: Re: Camera Lens's
Post by: razzo on 15 October 2009, 07:50:48
the focal length of the human eye is about 57mm so a standard 50 mm lens see's roughly the same, so a 300mm lens will magnify the image by around 6 times what the eye can see (6x50=300). I think lens size in mm is the distance of the focusing element of that lens is from the film plane on the camera
Title: Re: Camera Lens's
Post by: waspy on 15 October 2009, 09:19:37
Quote
The value in millimetres is the focal length (effectively the magnification). http://en.wikipedia.org/wiki/Focal_length.

Where there's a range of focal lengths it's a zoom lens that is continuously variable between the two extremes.

The other parameter of interest is the maximum aperture or f number (e.g f2.8) which relates to the maximum amount of light it will collect (the "brightness" of the image).http://en.wikipedia.org/wiki/F-number

You should be able to find some bargains on ebay. Film equipment goes for pennies these days.

I'm not aware of the mount that the OM10 had but I've got a couple of old lenses with a 42mm pentax screw mount if you want to experiment.

Kevin


PM sent :y