Valentina Caniglia Posted December 11, 2005 Share Posted December 11, 2005 Hi all, I am shooting a miniture commercial in 35mm. I am ordering the Arri macro 50mm and the arrimicro 100mm. I would like to know how many stop do I loose using a 50mm macro or 100 micro? How do you calclute the T stop when you have these lenses on? Do you just measure the light with lightmeter and calculate the stop loss in relationship? I would like to use a periscope lenses. How do I calculate the T stop with the periscope? If I use diopers +1,+2,+3,+4,+5 how much T- stope I loose? Thank You to all V. Link to comment Share on other sites More sharing options...
Daniel Stigler Posted December 11, 2005 Share Posted December 11, 2005 (edited) You can download info on exposure compensation for macros here: http://www.arri.de/sub/gb/rental/cam/ti/index.htm Use your lightmeter like you always do and then correct the stop according to the lens settings. (or have your AC do that....) You don't have to change your stop when using diopters. What periscope do you plan to use? You'll need a lot of light. At least a T8. Edited December 11, 2005 by Daniel Stigler Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted December 11, 2005 Premium Member Share Posted December 11, 2005 Hi all, I am shooting a miniture commercial in 35mm. I am ordering the Arri macro 50mm and the arrimicro 100mm. I would like to know how many stop do I loose using a 50mm macro or 100 micro? How do you calclute the T stop when you have these lenses on? Do you just measure the light with lightmeter and calculate the stop loss in relationship? I would like to use a periscope lenses. How do I calculate the T stop with the periscope? If I use diopers +1,+2,+3,+4,+5 how much T- stope I loose? Thank You to all V. Hi, The newer Arri Macro lenses are self compensating. As a rule of thumb 1:1 is always 2 stops. I often shoot watches, for a watch and strap packshot about 1/3 Stop, watch face in 1:185 about 1 stop. Periscopes usually lose about 1 stop but you should ask the rental company and ideally test! Stephen Link to comment Share on other sites More sharing options...
Valentina Caniglia Posted December 12, 2005 Author Share Posted December 12, 2005 Thank You to all for your response. I am not still clear though how much I have to open for Arri 50mm macro and arri 100mm macro. I would like to undertand the arri chart when it says 1:1 or 1:2 ect. Thanks a lot V. Link to comment Share on other sites More sharing options...
Premium Member Adam Frisch FSF Posted December 12, 2005 Premium Member Share Posted December 12, 2005 (edited) As Stephen says - the newer Macro lenses compensate themselves. This means that when you focus normally the lens has it's speciefied stop, say T4. When you go into macro-range, the lens automatically opens up the stop to compensate for the light loss, for example to T2.8. This will be clear to you when you see such a lens. The older ones don't compensate themselves. But that doesn't matter because clearly printed on them are a diagram that say how much you should open up the stop at this and that focus range to compensate. It's all printed on the barrell, so you can't go wrong. Diopters don't need compensating, but they also remove the lens possibility for infinity focusing, so you can't pull very much focus when you use them. And as a last resort - you can always overexpose when you're at normal focus and then let it go "darker" and arrive at the correct exposure when you're in macro. Then all you do is a dynamic in telecine to darken the image in the beginning - easy pie. Film can handle at least 2 stops of overexposure, even more, if need be. I've always argued that every lens should be a macro lens anyway. Don't need complicated compensating stops and such - all I need is close focus capability when I need it. It' such a hassle with diopters that never fit and get smear marks and thumbprints all over them. All the lens manufacturers have to do is make the lens have longer focus threads and that's it. Edited December 12, 2005 by AdamFrisch Link to comment Share on other sites More sharing options...
Premium Member Stephen Williams Posted December 13, 2005 Premium Member Share Posted December 13, 2005 Thank You to all for your response. I am not still clear though how much I have to open for Arri 50mm macro and arri 100mm macro. I would like to undertand the arri chart when it says 1:1 or 1:2 ect. Thanks a lot V. Hi, For the same image size you would open a 50mm or 100 mm lens the same amount. At the same F stop the DOF is also the same! 1:1 is when the image size on the negative is the same size as the object being filmed. 1:2 the object is twice the size of the image on the negative. Stephen Link to comment Share on other sites More sharing options...
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