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PostPosted: Mon Jan 31, 2011 12:03 am 
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I was shooting in a studio today with an 85/1.4 and had switched to a 50/1.8 for a couple shots. The exposure was obviously different so I had to readjust the strobes to compensate but could not achieve the same result. (was shooting at max aperture)

Do lenses render images differently or if I had a 50/1.4 could I had just swapped back and forth without needing to change any settings?


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PostPosted: Mon Jan 31, 2011 12:37 am 
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There is 1 stop difference between f1.4 and f1.8 so when shooting wide open you will have to re-adjust the lights. If both lenses were set to the same f stop, f4 for example no adjustment would be required.


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PostPosted: Mon Jan 31, 2011 1:01 am 
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Or you can adjust ISO rather than the lights, so you don't mess up your ratio, and it's a lot easier to adjust one control on the camera, rather than multiple lights.


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PostPosted: Mon Jan 31, 2011 10:28 am 
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Some lenses may render light differently at the same apertures even upto 1/3 of a stop also distance of model to light can change I would just re meter with your light meter and see what's happening


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PostPosted: Mon Jan 31, 2011 11:21 am 
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what do you mean by same results? Exposure changed?

If the lighting did not change, it should be consistent, but as Tyler said, some lenses could have small variables. Were they the same brand, make?

The other thing i thought of is with a differnt focal length, you probably changed your shooting spot. Maybe your new spot caught some flare or the new angle affected how much light was being bounced back at your camera.


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PostPosted: Mon Jan 31, 2011 1:53 pm 
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that could be it. good learning experience though. thanks again Ed :p now to find away to go through all the images


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PostPosted: Mon Jan 31, 2011 2:18 pm 
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Delsorbo wrote:
that could be it. good learning experience though. thanks again Ed :p now to find away to go through all the images


Would love to see some too. Im interested in seeing how others approach lighting in the studio space. And you gotta take me club shooting with you one time so i can try that too! ha


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PostPosted: Mon Jan 31, 2011 2:21 pm 
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um, 1.4 -> 1.8 is 2/3 stop

timras wrote:
There is 1 stop difference between f1.4 and f1.8 so when shooting wide open you will have to re-adjust the lights. If both lenses were set to the same f stop, f4 for example no adjustment would be required.


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PostPosted: Mon Jan 31, 2011 2:45 pm 
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Not only that but different lenses also transmit light differently and the f-stop represents the physical opening relative to the focal length. The T-stop represents the amount of light let through so that you'd have to light for each lens independently unless they have matched t-stops although generally you can get away with being in the same ballpark with the same f-stop.


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PostPosted: Mon Jan 31, 2011 3:26 pm 
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Learnt something new today. Thanks!
I had always thought f/1.4 = f/1.4 = f/1.4 regardless of lens.

Dimitris wrote:
Not only that but different lenses also transmit light differently and the f-stop represents the physical opening relative to the focal length. The T-stop represents the amount of light let through so that you'd have to light for each lens independently unless they have matched t-stops although generally you can get away with being in the same ballpark with the same f-stop.


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