Can you fit an ND grad filter onto a 500mm or 600mm lens?

StewartR

StewartR

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Stewart
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Yes
And if so, how?
 
Do they do grad drop ins? Can't imagine drop in is good for that kind of thing.

As a man with access to more high end lenses than anyone else on the forum I thought you'd know the answer to this!
 
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Whispers on the 'net that maybe a 52mm conventional screw in grad would fit the drop in slot?

Interested to know what you're planning, or is it just a curiosity thing?
 
I remember watching a video of how LEE make their filters and basically the were made in sheet form and then dipped in chemical to create the right effect...so in theory I guess they could make a larger sheet, the next hurdle would be fitting it, I guess you could have a holder fabricated with screw clamps that tighten on the outside of the lens body...all told it sounds bloody expensive though :eek:
 
Don't think that there's anything off the shelf but I would have thought that someone who's handy with tools could modify a drop in one swap the glass for a grad
 
You would have to make one to fit the rear drop-in slot, which wouldn't be too difficult, but I'm not sure how good or useful it would be.

Fitted to the front of a lens, grads have an almost invisible effect on anything over about 100mm, because they only 'look' through a small portion in the middle. And for the same reason, the filter must be very high optical quality as imperfections are greatly magnified and can impact sharpness. Using the rear drop-in slot changes things a bit, but I still wonder if it would be worthwhile. Better to add a grad effect in post processing, or use HDR technique.

Edit: easy to test. Get a bit of coloured cellophane off a sweet wrapper and attach it half way across the drop-in holder - see what you get.
 
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ACW said:
Whispers on the 'net that maybe a 52mm conventional screw in grad would fit the drop in slot?
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LCPete said:
Don't think that there's anything off the shelf but I would have thought that someone who's handy with tools could modify a drop in one swap the glass for a grad
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Thanks for the suggestion. The problem with that approach would be that (so far as I can see) you wouldn't have any control at all regarding how far up the picture the grad transition occurs. That could be a big restriction on composition.
 
HoppyUK said:
Fitted to the front of a lens, grads have an almost invisible effect on anything over about 100mm, because they only 'look' through a small portion in the middle.
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I don't understand. Can you elaborate please?
 
ACW said:
Interested to know what you're planning, or is it just a curiosity thing?
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Sure. It's just the usual thing you do with ND grads - photographing the sunrise.

There's a spot locally from where you can see Windsor Castle about 8 miles away on the horizon. For a few days each year the sun rises directly behind the castle. The only good opportunity this week was Thursday when I captured the image below with a 500mm lens (uncropped). But I couldn't help feeling that an ND grad would have been helpful.

960233_696070277084887_614976946_n.jpg
 
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StewartR said:
I don't understand. Can you elaborate please?
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On a wide-angle, the lens sees the full width of the filter, and a lot of the height too. As focal length increases, the angle of view narrows and cuts out a lot of the filter, particularly the height. Try it on something like a Canon 24-105 and the grad effect will change from strong at 24mm to much reduced at 105mm. Depth of field also has an impact, with higher f/numbers pulling the grad line more into focus, so it appears slightly darker.

Rear-drop-in filters obviously change this, but you'd have to suck it and see (see my edit above).

On a similar subject, just a nerdy point of interest really, I was puzzled when I noticed I got different grad effects on my 24-105 and 17-40, both at 24mm. Turns out it's because the entrance pupil is in different positions and that affects how much of the filter the lens actually sees at a given focal length.

Edit: easy way to see what's going on is to get a clear plastic ruler and stick it across the front of the lens with Blutack. Use live view, aim at a plain wall, focus on infinity. Set highest f/number like f/22 to pull the ruler into focus as much as possible, press depth of field preview button, see how things change as you zoom.
 
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HoppyUK said:
On a wide-angle, the lens sees the full width of the filter, and a lot of the height too. As focal length increases, the angle of view narrows and cuts out a lot of the filter, particularly the height. Try it on something like a Canon 24-105 and the grad effect will change from strong at 24mm to much reduced at 105mm. Depth of field also has an impact, with higher f/numbers pulling the grad line more into focus, so it appears slightly darker.
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I still don't understand why a 500mm f/4 lens has a 125mm front element if it's only using the central part of it, but I'll try the experiment. Thanks. I could also easily simulate a hard ND grad using the edge of a piece of welding glass, just to see what effect it has on the 500mm lens.
 
gramps said:
Camera Raw and software?
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Far too much noise in the shadows for my taste, unfortunately. I think this approach is pretty much a last resort, though if the weather's pants for the next opportunity in early/mid January and I can't be bothered to wait until next December, I may come back to this one and see what I can do with noise reduction software...
 
StewartR said:
I still don't understand why a 500mm f/4 lens has a 125mm front element if it's only using the central part of it, but I'll try the experiment. Thanks. I could also easily simulate a hard ND grad using the edge of a piece of welding glass, just to see what effect it has on the 500mm lens.
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Think about angle of view Stewart, which is 4 degrees at 500mm, side to side of full-frame. So (rough guess) it's only going to see something like 20-30mm of any filter attached to the front. You can't really do the ruler thing on a 500mm, as it will be so massively out of focus you won't see a sosij. But to get an idea of what's happening, try Blutacking a clear plastic rule across the front of a zoom lens and see how things change with focal length. As I mentioned above, lenses don't behave predictably according to focal length with grads, eg I just tried it with a 24-105 and while there's a significant difference in the amount of the ruler seen when zooming from 24-105, doing the same thing on a 17-40 changes things a lot more (because the entrance pupil moves around more).

Edit: short answer is HDR ;)
 
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StewartR said:
Far too much noise in the shadows for my taste, unfortunately. I think this approach is pretty much a last resort, though if the weather's pants for the next opportunity in early/mid January and I can't be bothered to wait until next December, I may come back to this one and see what I can do with noise reduction software...
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True, but that's using a 150Kb file don't forget, using your original RAW file should produce far better results.
 
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