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35mm macro lensing question...


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#1 Patrick Kaplin

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Posted 28 March 2009 - 01:39 PM

Ok, so I've grown quite accustomed to lensing projects in 16mm. I know my my focal lengths in relation to shots I wish to achieve. However I have my first shoot with 35mm lensing for a Red project coming up soon, and I'd like to know how the fov translates over.

So two questions essentially:

-I usually lens my CUs of subjects shooting 16mm with a 40mm. How would this translate over to 35mm? Not asking for aesthetic choice, just what kind of fov difference should I expect for 35mm versus 16mm in specific focal lengths.

-Also, one of the shots involves an extreme CU of a pin pricking someone's finger-tip. Very tight macro work, only the tip of the person's finger is in frame. What focal length macro lens should I choose to achieve this shot?

...40mm T2.1 Zeiss Macro
...50mm T3 Zeiss Macro
...60mm T3.0 Zeiss macro
...100mm T3.0 Zeiss macro
...200mm T4.0 Optex macro

Is the key to magnifying the subject even further to add extension tubes? Please excuse my lack of knowledge for macro-photography. Still learning ;-)
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#2 Chris Keth

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Posted 29 March 2009 - 03:22 AM

Basically just double the focal length you like for 16mm to get the focal length of equivalent field of view on (spherical) 35mm. I think for the fingertip shot, I would go right to the 200mm so you're not crowding in too close to the camera. I think that'll give you a working distance of 2 or 3 feet. I shot some super tight stuff of a pen writing and I used a 100mm and it got really close sometimes, I wished I had a longer lens. If possible, you might want to find a way that the person can rest their hand on something out of frame. Otherwise the pinpoint will sway in and out of focus pretty badly just with their breathing. Some sort of support will help control that.
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#3 Patrick Kaplin

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Posted 29 March 2009 - 09:55 AM

Basically just double the focal length you like for 16mm to get the focal length of equivalent field of view on (spherical) 35mm. I think for the fingertip shot, I would go right to the 200mm so you're not crowding in too close to the camera. I think that'll give you a working distance of 2 or 3 feet. I shot some super tight stuff of a pen writing and I used a 100mm and it got really close sometimes, I wished I had a longer lens. If possible, you might want to find a way that the person can rest their hand on something out of frame. Otherwise the pinpoint will sway in and out of focus pretty badly just with their breathing. Some sort of support will help control that.


Thank you much Chris! I was thinking probably around the 200mm range as well. Good idea for resting the person's hand on something! What do you think the best working t-stop would be for a shot like this? T-8? I still want a fairly shallow DOF, but I want to be able to see the needle and the fingertip almost completely in focus. Where could I find 35mm DOF charts for a 200mm macro? To get an impression of exactly how close I want this shot to be. I want to see only from the edge of the fingernail to the tip. The needle enters frame and pricks the finger. So close that we'd probably see some of the ridges of the finger prints in the person's finger. Do you think the 200mm can cover that?

Thanks!
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#4 Chris Keth

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Posted 29 March 2009 - 12:23 PM

Thank you much Chris! I was thinking probably around the 200mm range as well. Good idea for resting the person's hand on something! What do you think the best working t-stop would be for a shot like this? T-8? I still want a fairly shallow DOF, but I want to be able to see the needle and the fingertip almost completely in focus. Where could I find 35mm DOF charts for a 200mm macro? To get an impression of exactly how close I want this shot to be. I want to see only from the edge of the fingernail to the tip. The needle enters frame and pricks the finger. So close that we'd probably see some of the ridges of the finger prints in the person's finger. Do you think the 200mm can cover that?

Thanks!


Shooting that close up will require you to consult magnification charts for depth of field rather than regular depth of field charts. DoF charts are only good up to 10x the focal length or so then that formula starts to go out. My american cinematographer manual (9th ed) has the pertinent charts on pages 744 and 746. To shoot the fingertip pretty much full frame like that, you're basically at 1:1 magnificaion where the image in film is the same size as the real object. That, on a 200mm lens will be somewhere in the area of 4-5 feet away. You'll need to compensate exposure by 2 stops for light loss and, to get even a reasonable amount of DoF you'll want to light to a T32 or T45 and, with that compensation, shoot at a T16 or T22. Even at a T22 at 1:1 you'll only have 1/10" of depth of field.
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#5 Patrick Kaplin

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Posted 29 March 2009 - 01:23 PM

Shooting that close up will require you to consult magnification charts for depth of field rather than regular depth of field charts. DoF charts are only good up to 10x the focal length or so then that formula starts to go out. My american cinematographer manual (9th ed) has the pertinent charts on pages 744 and 746. To shoot the fingertip pretty much full frame like that, you're basically at 1:1 magnificaion where the image in film is the same size as the real object. That, on a 200mm lens will be somewhere in the area of 4-5 feet away. You'll need to compensate exposure by 2 stops for light loss and, to get even a reasonable amount of DoF you'll want to light to a T32 or T45 and, with that compensation, shoot at a T16 or T22. Even at a T22 at 1:1 you'll only have 1/10" of depth of field.


Awesome, good to know. Apparently need a lot more light than I originally thought!
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#6 Chris Keth

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Posted 29 March 2009 - 04:36 PM

Awesome, good to know. Apparently need a lot more light than I originally thought!


Yeah, when you start working with that much magnification, you start needing lots of light when you're tied to 1/50" shutter speed.

One trick I wanted to mention. When you light that shot, you may not be able to light the set behind to a deep enough stop to read on film if you want any depth of field at all on the macro subject. I fixed that problem one time when I was shooting that pen writing that I mentioned by making a paper backdrop. It was only a little drawing on 8.5x11 paper I did in colored pencil that approximated the colors, shapes and lighting accents I wanted. It was so out of focus that it really played well for the room we were in. I lit the pen for those shots with a 2k about a foot and a half away with some light diff on the doors and that little backdrop just got a flat frontal 1K and it worked pretty well.

Hopefully someone else will chip in who has more macro experience that I have. My experience is pretty limited, but it turned out well.

Edited by Chris Keth, 29 March 2009 - 04:36 PM.

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#7 Patrick Kaplin

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Posted 29 March 2009 - 07:51 PM

Yeah, when you start working with that much magnification, you start needing lots of light when you're tied to 1/50" shutter speed.

One trick I wanted to mention. When you light that shot, you may not be able to light the set behind to a deep enough stop to read on film if you want any depth of field at all on the macro subject. I fixed that problem one time when I was shooting that pen writing that I mentioned by making a paper backdrop. It was only a little drawing on 8.5x11 paper I did in colored pencil that approximated the colors, shapes and lighting accents I wanted. It was so out of focus that it really played well for the room we were in. I lit the pen for those shots with a 2k about a foot and a half away with some light diff on the doors and that little backdrop just got a flat frontal 1K and it worked pretty well.

Hopefully someone else will chip in who has more macro experience that I have. My experience is pretty limited, but it turned out well.


Haha, I was actually thinking of doing the something along the same lines when I was considering the bg for this shot. Do you have any footage of the shot that you can post?
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#8 Chris Keth

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Posted 30 March 2009 - 12:39 AM

Haha, I was actually thinking of doing the something along the same lines when I was considering the bg for this shot. Do you have any footage of the shot that you can post?


I don't have any footage very handy from that, sorry.
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#9 Satsuki Murashige

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Posted 30 March 2009 - 01:46 AM

Hi Patrick,

I shot a macro lens test using some of those lenses and a Red camera back in December. I've uploaded some large frame grabs here with descriptions: http://www.flickr.co...2187735/detail/.

You should be able to click on them and see a large pic. I've included the distance measured from the subject to the focal plane.

The lenses are: 60mm Arri Zeiss Macro, 100mm Arri Zeiss Macro, 200mm Arri Zeiss Macro, and a Zeiss Superspeed Mk.2 85mm with a 2x extender and diopters. All shots were taken wide open. I found that the Superspeed combo looked the worst and needed to be stopped down to T4 to look decent. The Arri Macros have variable maximum apertures that close down automatically as you focus closer. They looked best stopped down to around T11 when focused closer than 1'6". Of course, we ended up shooting with them on set wide open. :rolleyes:

I like to shoot CUs in 35mm with the 85mm. But be careful, focus is extremely critical at those focal lengths. Make sure you've got a great 1st AC or give them a reasonable stop to work at, make sure your lenses tape out, etc.

Edited by Satsuki Murashige, 30 March 2009 - 01:49 AM.

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#10 Patrick Kaplin

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Posted 30 March 2009 - 12:32 PM

Wow, thanks Satsuki!

The photos look great and give me a good impression of judging the distances, focal lengths and f-stops. Thanks for posting!

When you say make sure your lenses tape-out, do you mean ensure the lenses are collimated properly by adjusting the back-focus and checking distance markings on each lens?
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#11 Chris Keth

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Posted 30 March 2009 - 02:27 PM

When you say make sure your lenses tape-out, do you mean ensure the lenses are collimated properly by adjusting the back-focus and checking distance markings on each lens?


Yeah, it's a combination of that and making sure the FFD on your camera is properly set.
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#12 Satsuki Murashige

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Posted 30 March 2009 - 07:31 PM

No prob, glad to help.

When you say make sure your lenses tape-out, do you mean ensure the lenses are collimated properly by adjusting the back-focus and checking distance markings on each lens?

Yes. I had a 35mm shoot a few months ago where 85mm Mk.2 Superspeed we were using was off by about 3". As you know, the Superspeeds have very poorly spaced marks on the barrel compared to modern lenses. That 3" doesn't seem like much, but if your focus puller is a few degrees off on the barrel then that compound error is the difference between the actor's eyes being in focus or his shirt being in focus.

I feel the situation is worse with the Red because: 1) focus is hyper-critical and unforgiving in 4K, moreso than in 35mm; 2) the backfocus ring adds another variable element that needs to be constantly checked and doesn't provide a benchmark to test the collimation of the lenses. Unless the lenses come from a decent rental house with a lens projector, who knows if they're actually collimated or not? I've had to deal with a set of Superspeeds where each lens had a different on the mark on the Red's backfocus ring. You can imagine how much fun that was to deal with on a daily basis. :(
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#13 Chris Keth

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Posted 31 March 2009 - 12:38 AM

I feel the situation is worse with the Red because: 1) focus is hyper-critical and unforgiving in 4K, moreso than in 35mm; 2) the backfocus ring adds another variable element that needs to be constantly checked and doesn't provide a benchmark to test the collimation of the lenses. Unless the lenses come from a decent rental house with a lens projector, who knows if they're actually collimated or not? I've had to deal with a set of Superspeeds where each lens had a different on the mark on the Red's backfocus ring. You can imagine how much fun that was to deal with on a daily basis. :(


That sounds miserable, Satsuki. I'll add one to your list of why it can be worse with the RED: 3. Rather than it being you and the operator seeing soft shots and then coming up with a solution to a "technical problem", the whole set is watching your takes go soft and then freaking out about it. Can you tell that sometimes I'm not so thrilled about a crowd watching your work in realtime 720P?
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