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01-05-2013, 08:47 AM   #1
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Inputting focal length

When using a manual lens on my K5, should I enter the 35mm equivalent focal length or the focal length of that lens i.e., my Nokton 58 lens, should I just enter 55, or should I multiply the focal length by 1.5 (87)for the crop sensor?

01-05-2013, 08:58 AM   #2
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input the actual focal length of the lens in use - or as close to it as allowed by the Shake Reduction menu.
01-05-2013, 09:03 AM - 1 Like   #3
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Well it's asking for the focal length doesnt it, don't over think it


focal length is a lens property and it does not change by the sensor size of the camera.
01-05-2013, 10:42 AM   #4
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Thanks!

01-05-2013, 02:22 PM   #5
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For the Nokton 58mm, you must enter 55 mm for MF lens.

You enter the closest (and lowest) focal length. This is used for the SR algorithms.
01-05-2013, 04:08 PM   #6
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when considering the SR algorithms, I think about the rule of thumb for shutter speed vs focal length, eg, 100mm lens, minimum shutter speed 1/100th. so.....I read somewhere that an aps-c dslr should use the 1.5x rule where 100mm lens needs 1/150th...just wondering about that
01-05-2013, 04:25 PM   #7
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QuoteOriginally posted by Franky2step Quote
when considering the SR algorithms, I think about the rule of thumb for shutter speed vs focal length, eg, 100mm lens, minimum shutter speed 1/100th. so.....I read somewhere that an aps-c dslr should use the 1.5x rule where 100mm lens needs 1/150th...just wondering about that
Not if you are using shake reduction (SR) ... although as you point out this is a 'rule of thumb', not a 'law of physics', and it applies to the average photographer. If you are the rock steady type, you might be able to shoot even slower hand held, or if you are the type that jams down the shutter button, you may need a higher shutter speed. I shoot my cameras the same way I shoot my guns; breath control, slow steady release, and still I use a camera support whenever possible even at high shutter speeds.
01-06-2013, 05:42 AM   #8
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QuoteOriginally posted by Franky2step Quote
when considering the SR algorithms, I think about the rule of thumb for shutter speed vs focal length, eg, 100mm lens, minimum shutter speed 1/100th. so.....I read somewhere that an aps-c dslr should use the 1.5x rule where 100mm lens needs 1/150th...just wondering about that
That is different from entering focal length for SR. The hand held speed is based upon acceptable sharpness of a print blown up to 8x10 inch from 35mm negative. If you consider using an APS C sensor, which crops the middle out of the frame, to get to 8x10 print you enlarge the image further, this is why the hand held speed needs to be increased for APS C sensors.

Using shake reduction if you have good technique will allow the rule of thumb to be pushed about 2-3 stops, although once, hand held, I shoot a 500 mm lens using SR at 1/40. That is about 4-1/2 stops slower than the "Rule"

01-06-2013, 06:13 AM   #9
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Like Lowel said that rule of thumbs is for the shutterspeed while handheld holding.

The SR needs to know the focal length because it needs to know how much it needs to move the sensor.
It moves differently for 28mm then with 100mm so you need to input the correct length or else it will actually blur the image
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