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Old Nov 25, 2006, 8:35 PM   #1
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Camera Math Question.

I have a Panasonic FZ30 and use a Nikon teleconverter TCE17. This gives me a total of 680mm

With my coming Pentax K10D and the Sigma 50 to 500mm lens with a 1.4 converter I end up with 700mm

Thanks for any answers

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7
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Old Nov 25, 2006, 9:52 PM   #2
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Hey Roger,
I am not sure, but I believe the Panasonic focal length is in 35mm equivelant. Because of the 1.5 crop factor on the Pentax, your 500mm lens would give a 750mm 35mm equivelant field of view even without the teleconverter. With the teleconverter it should be right around 1000mm.

Tim
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Old Nov 25, 2006, 10:39 PM   #3
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Focal length is the distance from the focal point of the lens to the film plane or sensor.

That does not change just because the sensor is smaller, only the field of veiw does. With a TC, the focal length does change by the power of the TC, which will take a 500mm lens and make it a 1000mm lens with a 2x TC.

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Old Nov 25, 2006, 10:43 PM   #4
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with that setup, you would get a focal length of 700mm and the viewing angle of a 1050mm lens.
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Old Nov 26, 2006, 9:55 AM   #5
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Hi Tim, thanks for trying to help me out. I have printed your post so I can try and understand what you said.

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7


NonEntity1 wrote:
Quote:
Hey Roger,
I am not sure, but I believe the Panasonic focal length is in 35mm equivelant. Because of the 1.5 crop factor on the Pentax, your 500mm lens would give a 750mm 35mm equivelant field of view even without the teleconverter. With the teleconverter it should be right around 1000mm.

Tim
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Old Nov 26, 2006, 9:56 AM   #6
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Tom, thanks for trying to help me out. I am printing what you said so I can get on the internet and try to figure out what it is you said.

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7

ennacac wrote:
Quote:
Focal length is the distance from the focal point of the lens to the film plane or sensor.

That does not change just because the sensor is smaller, only the field of veiw does. With a TC, the focal length does change by the power of the TC, which will take a 500mm lens and make it a 1000mm lens with a 2x TC.

Tom
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Old Nov 26, 2006, 9:57 AM   #7
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TDN, thank you for trying to help me out.

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7


TDN wrote:

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with that setup, you would get a focal length of 700mm and the viewing angle of a 1050mm lens.
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Old Nov 26, 2006, 10:05 AM   #8
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I am going to try another question that maybe will let me understand.

My spotting scope is 25 to 60 power, my FZ30 is 12 power and the teleconverter 1.7 makes it 20.4 power.

A sigma 50 - 500 is what power ??? At 500 plus 1.4 for the teleconverter it would be 700 ??? At 500 plus the teleconverter the animal will look much closer than at the 50 mark ???

With a 1.4 added what power is it ???

Thanks to all of you who are trying to help me out but I have no idea what you are saying. I have printed all the posts and I will get on the internet and try to understand.

Thanks again

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7

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Old Nov 26, 2006, 11:21 AM   #9
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thehotel wrote:
Quote:
A sigma 50 - 500 is what power ??? At 500 plus 1.4 for the teleconverter it would be 700 ??? At 500 plus the teleconverter the animal will look much closer than at the 50 mark ???
Roughly speaking, at the 500 mark, you have 10 times the magnification you do at the 50 mark. All you have to do to figure that out is divide the long focal length by the small one. So the 700 you get with the teleconverter is 700/50=14 times the magnification.

On a film camera that would translate to a 10 power and a 14 power zoom over the human eye.

On a film camera, that 50mm lens would give roughly 0 magnification. To get the same effect using a Pentax DSLR, you need to use a lens that is approximatly 33mm. (This is where that 1.5 multiplier for the Pentax DSLRs comes in to play).

So, on the Pentax DSLRs, you need to multiply the previously computered values by 1.5 again, so the 500 gives you roughly a 15 power zoom over the human eye and the 700 gives you roughly a 21 power zoom over the human eye.

Quote:
With a 1.4 added what power is it ???
It's a 1.4 power magnifier by itself.

Paul
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Old Nov 26, 2006, 11:35 AM   #10
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Paul, Thank You, Thank You, Thank You

TOTALLY WACKY roger
FZ 30, Nikon TCE17, QuikAim Max RDS, Zeiss Digiscope/Sony W7


pbender wrote:
Quote:
thehotel wrote:
Quote:
A sigma 50 - 500 is what power ??? At 500 plus 1.4 for the teleconverter it would be 700 ??? At 500 plus the teleconverter the animal will look much closer than at the 50 mark ???
Roughly speaking, at the 500 mark, you have 10 times the magnification you do at the 50 mark. All you have to do to figure that out is divide the long focal length by the small one. So the 700 you get with the teleconverter is 700/50=14 times the magnification.

On a film camera that would translate to a 10 power and a 14 power zoom over the human eye.

On a film camera, that 50mm lens would give roughly 0 magnification. To get the same effect using a Pentax DSLR, you need to use a lens that is approximatly 33mm. (This is where that 1.5 multiplier for the Pentax DSLRs comes in to play).

So, on the Pentax DSLRs, you need to multiply the previously computered values by 1.5 again, so the 500 gives you roughly a 15 power zoom over the human eye and the 700 gives you roughly a 21 power zoom over the human eye.

Quote:
With a 1.4 added what power is it ???
It's a 1.4 power magnifier by itself.

Paul
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