Exposure compensation for Rolleinar needed?

[rince]

Hi,

I just purchased Rolleinar II+III close up lenses for my Rolleiflex and I am trying to find out if they need a compensation factor or not. would be great if someone could help me out with a hint. Otherwise I will just have to bracket a few exposures and see for myself.

Thanks in advance,
Dennis


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[Two23]

Seems to me that they do not change exposure, because the aperture and the actual length of the lens stays the same. It's when you start adding extension tubes that this changes.


Kent in SD

 

[rince]

Thank you.


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[Peltigera]

When you use a close-up lens, the light going into the camera is coming from a smaller area so for the same subject illumination there will be less light going into the camera than there would be without the close-up lens. I would have thought some exposure compensation was needed.

 

[Bob Marvin]

I've been using Rolleinars for years; NO exposure compensation is needed. AFAIK this applies to ALL close-up lenses (but the Rolleinars are the only ones I've ever used).

 

[BrianShaw]

No compensation required (as others have also attested).

 

[rince]

Thank you all!

 

[ic-racer]

"close up" lenses change the focal length of the taking lens to obtain focus, avoiding the need to crank the lens far from the film and avoiding the need for a bellows extension factor.

 

[Richard S. (rich815)]

As already said, Rolleinar needs no compensation, you may be thinking of extension tubes....

 

[JPD]

When you use a close-up lens, the light going into the camera is coming from a smaller area so for the same subject illumination there will be less light going into the camera than there would be without the close-up lens. I would have thought some exposure compensation was needed.

The close-up lens actually shorten the focal length, so it's like moving in closer with a wide angle lens.

In theory the lens gather a little more light with a close-up lens on.

Plus lenses were one sold for large format cameras as cheap wide angle accessory lenses. With a shorter draw on the bellows you could focus at infinity. And minus lenses were used to make the focal length longer. Zeiss had their Protar and Distar lenses for these purposes.

 

[piu58]

> In theory the lens gather a little more light with a close-up lens on.

Yes, but from a smaller area. The effects equalize each other.

 

[JPD]

> In theory the lens gather a little more light with a close-up lens on.

Yes, but from a smaller area. The effects equalize each other.

I thought about that, but wasn't sure because a normal lens with a close-up lens on becomes a wide-angle.

 

[BrianShaw]

Think in terms of "bellows extension" (distance of lens from film plane) rather than acceptance angle of the lens and you'll have an easier time understaning the need (or no need) for exposure compensation when using close-up attachments.

 

[JPD]

Think in terms of "bellows extension" (distance of lens from film plane) rather than acceptance angle of the lens and you'll have an easier time understaning the need (or no need) for exposure compensation when using close-up attachments.

That must be correct! Thanks.

 

[piu58]

> Think in terms of "bellows extension" (dista

Indeed you have a bellow extension: The new lens (made from Planar and Rolleinar) has a shorter focal length and is extended even at the infinity mark. But the shorter focal length leads to a larger f/stop:
Because the aperture remains the same, the actual f-stop will be increased. This compensates the bellow extension.

 

[BrianShaw]

... This compensates the bellow extension.

So the net impact on exposure is, what, about zero... right?