From kit to prime - conversion issues

Lorica

Lorica

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sarah
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Hiya boys and girls :)

So I'm still hankering over a prime, either 35 or 50mm and so I've been playing with these two lengths on my kit lens to help me make a decision. And then I thought ..
would the prime lens give the same images on my cropped sensor (d3000) as they would with the kit lens? Would they look different?
I dont want to like the look of a 50mm on my kit, only to find that in reality I get an 80mm on the 50mm prime and so need to swap lenses pretty quick lol.
 
35mm on a primes is the same 35mm on a kit lens no matter what camera they are both used on.. if you change camera from crop to full frame or other way.. then the focul leangth changes..

otherwise you ahve the right idea so keep testing :)
 
What are you taking pictures of mostly?
 
KIPAX said:
35mm on a primes is the same 35mm on a kit lens no matter what camera they are both used on.. if you change camera from crop to full frame or other way.. then the focul leangth changes..

otherwise you ahve the right idea so keep testing :)
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Not strictly true, the field of view changes to that of a focal length equivalent to the cropping, the focal length does not change, it "appears" as if focal length changes but as focal length is down to the lens the camera body has no input.
Therefore a 50mm lens (kit or prime) will give the equivalent image of an 80mm lens on a 1.6 crop body (or 65mm on a 1.3 crop body).

Matt
 
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Just confirm, as Tony says, 50mm on your kit lens will give the same image as using a 50mm prime or any other 50mm lens for that matter. The focal length is always quoted using the same standard no matter what camera sensor the lens is designed for.

There is a longer winded version but the above is all you really need to know to answer your question
 
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KIPAX said:
Are you saying....A kit lens at 35mm on camera A and a prime at 35mm on camera A give different focul leangths ?
Click to expand...

No they give identical images on the body they are mounted onto. They give the appearance of different focal lengths on different bodies i.e. 1.6, 1.3 of FF but the focal length does not change, it cant, its how far from the front (or rear) element the image focuses behind the lens onto the film or sensor (hence the term focal length).
 
MatBin said:
No they give identical images on the body they are mounted onto. .
Click to expand...

Exactly what I said just before you said not strictly true..

Read the OPs question and what she is trying to achieve.. I gave a clear answer so she understands that testing her kit at 35mm will show her the same focul leangth as the 35mm prime.. thats the answer to her question..
 
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I'd be even more picky as I'm not happy with the whole idea of converting lens lengths as you don't get exactly the same look, for example, with 30mm on APS-C as you would with 50mm on full frame. So I personally always think of 30mm on APS-C as giving the same look as the centre portion cut from a 30mm full frame image if the pictures are taken from the same distance.

You would probably take the shot from the same distance if shooting with either 30mm on APS-C or 50mm on full frame and the field of view would be the same but the images are never going to look exactly the same as the 50mm will probably bring the background forward slightly more with all the implications for depth or lack of etc.

It's a messy subject but I think that the easiest way to think about it is that when doing things like comparing 30mm APS-C to 50mm full frame the field of view will be the same - but that's all.
 
Lorica said:
Hiya boys and girls :)

So I'm still hankering over a prime, either 35 or 50mm and so I've been playing with these two lengths on my kit lens to help me make a decision. And then I thought ..
would the prime lens give the same images on my cropped sensor (d3000) as they would with the kit lens? Would they look different?
I dont want to like the look of a 50mm on my kit, only to find that in reality I get an 80mm on the 50mm prime and so need to swap lenses pretty quick lol.
Click to expand...

A prime lens acts exactly the same as your zoom. What your zoom looks like at 35mm is what a 35mm prime will give you.

The advantage of a prime is that you get a wider aperture giving you more control over depth of field and enabling you to possibly use faster shutter speeds and/or lower ISO's. A prime lens may also be more compact than your kit lens.

A prime lens may have some image quality advantages over your kit lens if you compare images taken at the same aperture, but, differences may be negligible.
 
I think she understands the whole focal length thing now!

I got a 50mm prime when I first changed lenses, but found myself struggling to get everything in the frame. Fine for portraits, not ideal for walkabout shooting. So I got a 28mm prime and it's great. 28 on my canon body (1.6 crop) equates to 44.8mm, slightly wider than the 'standard' 50mm, which I find perfect.

I still prefer the flexibility of a zoom though, so I'm getting a 24-105 (today,woo) for walkabout and will keep the 28 for low light and indoors.

Hope that helps!
 
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