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06/15/2005 03:07:00 PM · #1 |
I am new to DSLR ( please be gentle) I have an olympus 2100 UZ with 10x optical zoom. 7-70 I also have a Nikon D 70 with the kit lens 18-70
When zooming in with my olympus I can reach much further than I can with the D70.....
Just what do these numbers mean. Is there a web site that will explain it to me?
I am thinking about a trip to Wyoming and am considering a new lens but first I think I need to know what the numbers mean in order to make a good decision. Thanks Mary |
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06/15/2005 03:12:35 PM · #2 |
You will have to think about it in terms of what they would mean in 35mm film scenario. 7-70mm is equivalent to 38mm-380mm while the kit lens from Nikon 18-70 is equivalent to 27mm-105mm only. That's why you can zoom in more with your olympus.
To get the similar zoom, look into Nikon 70-200 or 70-300mm zoon lenses.
( I know this is not a very descriptive reply, but I got to run now )
hope this helps
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06/15/2005 04:45:40 PM · #3 |
basically the larger the second number is, the further you can zoom. |
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06/15/2005 05:04:17 PM · #4 |
Originally posted by peterish:
basically the larger the second number is, the further you can zoom. |
that is, if the numbers are first converted to the 35mm equivalent numbers. |
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06/15/2005 05:12:34 PM · #5 |
try here.
Basically there is no direct equivalent because the numbers mean different things. Generally, the "10x zoom" figure quoted for point and shoots is essentially meaningless. It means that its lens' longest focal length is 10 times its widest. If it's a 50mm lens at its widest for instance, at its logest it'll be 500mm.
Generally the focal length of a lens is only one guide to how large the image will appear, it also depends on the size of your sensor or film plane. Point and shoots have tiny sensors, which allows them to have very small lenses that often have really short focal lengths at their widest. This is where "35mm equivalent focal length" comes in - it takes account of the size of the sensor, and tells you what that lens would be if it were used on a 35mm film frame or a full-frame sensor.
Generally the best way to get used to understanding focal length is simply by experimenting and looking through the viewfinder with different lenses until you get used to how much "zoom" you can expect to get from what lens.
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06/15/2005 11:40:48 PM · #6 |
Originally posted by riot:
try here.
Oh, my that site was confusing... I did not understand any of the math on that page. Algebra was an A for me but that was a LONG, LONG time ago!
Generally the best way to get used to understanding focal length is simply by experimenting and looking through the viewfinder with different lenses until you get used to how much "zoom" you can expect to get from what lens. |
Yes, this would probably be best but in rural Missouri we have critters- like ticks and chiggers but few photography stores with real lenses. Best Buy does stock one lens ....
Thanks for explaining the reason my 7-70 reaches further than my 18-70. Mary |
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06/15/2005 11:49:23 PM · #7 |
Originally posted by WildflowerJoy:
.
When zooming in with my olympus I can reach much further than I can with the D70.....
J |
I am not familiar with your cameras, but depending on the size of your sensor determines the focal length of your lens.
Even though you may have a reach of 70mm, one sensor on your camera is probley a 1:2, OR 1:3 scale.
Like I said, I don't know your camera, but my Rebel 300 D has a sensor that if I had a 70mm lens, I would have to times that lens by 1.6 to get the accuracy of my reach because of the size of my sensor. IE, 70 x 1.6 = 112mm. ( Did I do my math right?)
Message edited by author 2005-06-15 23:50:34.
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06/16/2005 08:56:37 AM · #8 |
Originally posted by swinging_johnson_v1:
Originally posted by WildflowerJoy:
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When zooming in with my olympus I can reach much further than I can with the D70.....
J |
I am not familiar with your cameras, but depending on the size of your sensor determines the focal length of your lens.
Even though you may have a reach of 70mm, one sensor on your camera is probley a 1:2, OR 1:3 scale.
Like I said, I don't know your camera, but my Rebel 300 D has a sensor that if I had a 70mm lens, I would have to times that lens by 1.6 to get the accuracy of my reach because of the size of my sensor. IE, 70 x 1.6 = 112mm. ( Did I do my math right?) |
Indeed, the 300D's sensor is 22.7 x 15.1 mm in size which gives a 1.54 focal length multiplier (35/22.7).
The D70's sensor is 23.7 x 15.5 mm giving a 1.48 focal length multiplier. So given a 70mm lens, the D70 will make it act like a 104mm lens. Now, here's the comparison: Your olympus has a sensor size 6.40 x 4.80 mm (told you they were tiny!). That's a 5.47x multiplier. To get a 104mm equivalent focal length on that, your lens would only need to be 104/5.47 = 19mm!
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