Posted by: comment anonymously? on September 30, 2008 at 12:31 PM
UV filter, focal lengths
UV filters serve no (positive) optical purpose on a digital SLR. However they protect the front of the lens, which is what he was concerned about - lenses scratching each other.
Anyone know why you use a 100mm-50mm combo, and what other combinations work?
Posted by: Jachym on September 30, 2008 at 12:34 PM
UV filter
...is there to protect the lenses from scratching each other. In worst case, you end up replacing a UV filter worth a couple of bucks...otherwise you would have to replace both lenses, which would end up being much more expensive.
On a reversed lens set-up, an inverted lens with a wider or lower focal length number will yield greater magnification. Higher focal lengths above 50mm will not produce enough magnification. To calculate the ratio, you just divide the focal length values of the coupled lens like this: lens A / lens B = magnification ratio. For example, a reversed coupled 200mm/50mm will give you 4:1 magnification ratio (200/50=4 or 4:1). While a 100mm/50mm combo will give you a ratio of 2:1. Imagine if you combine a 200mm with an inverted 24mm prime it will give you a ratio around 8.3:1... ;-)
On a reversed lens set-up, an inverted lens with a wider or lower focal length number will yield greater magnification. Higher focal lengths above 50mm will not produce enough magnification. To calculate the ratio, you just divide the focal length values of the coupled lens like this: lens A / lens B = magnification ratio. For example, a reversed coupled 200mm/50mm will give you 4:1 magnification ratio (200/50=4 or 4:1). While a 100mm/50mm combo will give you a ratio of 2:1. Imagine if you combine a 200mm with an inverted 24mm prime it will give you a ratio around 8.3:1... ;-)
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"How to create the illusion of high-resolution macrophotography: Step 1: Begin by using a high-resolution macroscopic photograph. Step 2: Done."
haha, real leet hax there.
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… and the illusion of superiority is just as easy to create by accusing someone ofcheating.
xxoo, keep it constructive please.
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I added this one to the Make Group. It's actually pretty easy to do, I ended up using my tripod to help with shaking.
http://farm4.static.flickr.com/3243/2902653150_af41bc2683_b.jpg
Brendon
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What was the point of the UV filter? He never said why he "wasn't concerned." Without them will bad things happen?
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UV filters serve no (positive) optical purpose on a digital SLR. However they protect the front of the lens, which is what he was concerned about - lenses scratching each other.
Anyone know why you use a 100mm-50mm combo, and what other combinations work?
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...is there to protect the lenses from scratching each other. In worst case, you end up replacing a UV filter worth a couple of bucks...otherwise you would have to replace both lenses, which would end up being much more expensive.
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Sweet, I have both those lenses. And almost that camera.
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In fact just reversing a good telephoto on your camera will work. Take a 300mm. hand hold it in front of your slr and snap you'll be amazed.
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On a reversed lens set-up, an inverted lens with a wider or lower focal length number will yield greater magnification. Higher focal lengths above 50mm will not produce enough magnification. To calculate the ratio, you just divide the focal length values of the coupled lens like this: lens A / lens B = magnification ratio. For example, a reversed coupled 200mm/50mm will give you 4:1 magnification ratio (200/50=4 or 4:1). While a 100mm/50mm combo will give you a ratio of 2:1. Imagine if you combine a 200mm with an inverted 24mm prime it will give you a ratio around 8.3:1... ;-)
Reply to this comment
On a reversed lens set-up, an inverted lens with a wider or lower focal length number will yield greater magnification. Higher focal lengths above 50mm will not produce enough magnification. To calculate the ratio, you just divide the focal length values of the coupled lens like this: lens A / lens B = magnification ratio. For example, a reversed coupled 200mm/50mm will give you 4:1 magnification ratio (200/50=4 or 4:1). While a 100mm/50mm combo will give you a ratio of 2:1. Imagine if you combine a 200mm with an inverted 24mm prime it will give you a ratio around 8.3:1... ;-)
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