Shooting A G Lens on Manual Film Camera

... with a little hacking.

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DX lens on film (cropped).

The poor-man’s option to get breathtaking ultra-wide angles. Without any hacking, all G lenses only work with minimum aperture on manual film cameras. Why? Because there’s not an aperture ring to select aperture, thus the diaphragm blades contract (stop down) till the minimum aperture.

Here’s the lens I hacked and shot on film with my trusty Nikon FA: AF-S 18-105mm f/3.5-5.6G DX. It’s the kit lens of my D90 body.

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Oops. Look at the gold paint. It has faded. I’ve been using this lens quite frequently, that’s why.

Well this lens is what I needed for a real 18mm shot (with black sides, of course, as this is a DX lens with smaller image circle). As mentioned, you can’t control the aperture of a G lens when mounted on a manual focus film camera. So how to get a bright, decent, and non-fuzzy shot with it?

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Simple. Just hack it.

Exposing the mount-side of any G lens you’ll see this small, movable pin. It is the aperture pin. Try look through your lens while fiddling with this pin. You will notice the aperture blades opening and closing as you move it.

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When left untouched, this pin springs to its normal position where the aperture is the smallest. Thus, to make it open, simply fold a small piece of paper and stuck it on the pin. Depending on what aperture value you want, you can choose to open the aperture partially or completely. In this photo below I’ve opened the aperture to a value of around f/8. Note that you can only select one aperture as the aperture is fixed using this method.

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Then the fun begins. Mount it on your full-frame manual film camera and look through the viewfinder. 18mm! Purely orgasmic, I tell you. So now, the problem lies on metering. This is a little tricky. Firstly, switch to aperture-priority mode and hold down the depth-of-field preview button/knob. Now the viewfinder looks dark and the shutter speed reading changes (stop-down metering). Now, remember the shutter speed and release the d.o.f preview button/knob.

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Switch to manual mode and dial in the shutter speed you remembered. Now this will give you the correct exposure. The logic is as follows: in A mode, the camera thinks that the lens is wide-open as it is a G lens (without aperture signal post). Thus if you take a photo immediately, it will be underexposed as the actual aperture is smaller than that. When you use stop-down metering, you’ve presented the camera the real aperture value and thus the complement shutter speed gives the correct exposure. If you’re unsure about it, use print films as it has an extremely wide dynamic range.

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Take note that it is not advisable to leave the lens (with paper stuck on its aperture pin) on the camera for too long (like, more than 15 minutes) as it may damage the depth-of-field preview mechanism. This is due to mechanical interference. I’ve once encountered this problem (my d.o.f lever went loose and died) but after I took a shot it sprung back to life again. Beware.

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WARNING: Hacking your lens in this way may result in damages to your lens or camera body. I DO NOT hold responsibility for any loss or damage done to your equipments if you shall follow my steps. This article is just for reference purpose only.

P.S: New dream lenses team: Tokina 11-16 f/2.8, Tamron 17-50mm f/2.8, Nikkor 70-200 f/2.8. Awesome.

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