Crop factor lens hood equivalence

chris malcolm

chris malcolm

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A full frame lens will be supplied with a lens hood appropriate to the angle of view of the lens on a full frame camera body. A crop sensor camera body using the same lens will have a narrower field of view. Consequently there could be a light source within the angle of view of the lens hood, but outside the angle of view of the sensor. That would cause flare and veiling in the image which would be removed if the lens were fitted with a longer or narrower lens hood with the appropriate angle of view for the crop sensor. The question is how much? Does the use of too wide a lens hood cause enough of a hit in image quality in enough cases to matter?

I note too that the expensive lens hoods which sometimes come with expensive lenses are sometimes very much blacker inside than the black plastic used in cheap lens hoods. That means for example that patches of the lens hood which are illuminated by the sun will reflect less light into the lens than the rather light black of the usual self-coloured black plastic.

Are we crop sensor camera users taking a significant hit in image quality by not changing the lens hoods on our full frame lenses?
 
as I recall when crop cameras first appeared there were some optional lenshoods suggested, but that's a long time ago in a far away place.

Short answer though... you're perfectly correct.
 
The only lens I've ever had that came with an additional 'DX' lens hood was a sigma 105mm macro lens. There was an additional bit that clipped between the 'fx' hood and the camera. The only problem was the length of the lens hood was nearly the same as the minimum focus 1:1.
 
To be filed in the "life's too short to worry about it" bucket.

Maybe yes, in some circumstance, if you squint and turn your head sideways but really there are more important things to be worried about.
 
What an interesting question :D

I'm sure I once bought a lens that came with two hoods, one APS-C and one FF but I can't remember which lens it was.

If it helps at all... I used FF lenses on my Canon APS-C DSLR's and I still do occasionally on my MFT cameras and with a hood fitted I can't remember any problems slapping me in the face so I'm tempted to say that although this is an interesting question and could be real world issue I think that mostly it'll be something we maybe shouldn't worry too much about.
 
Perfectly true, but the effect of a less than optimum lens hood is debatable in most situations, though certainly not all, and lens hoods always provide excellent physical protection. Most people use zooms, and the lens hood can only ever be at optimum efficiency at widest focal length. A couple of exceptions are the old version Canon and Nikon 24-70/2.8s that are optically reversed, meaning they're physically longest at the wide end, allowing for a lens hood that effectively zooms with focal length. This feature has been dropped with the latest versions.

It's also true that cheapy lens hood are not very well blacked inside. I've seen examples where they actually make things worse by reflecting side lighting into the lens. I have a couple of cheapies and I line them with black self-adhesive felt - very easy, 72p from Hobbycraft :) I've also made a DIY zooming lens hood that I use for white background work in the studio. In extreme situations like that, it does make a difference. It's pictured in post #27 in this thread https://www.talkphotography.co.uk/threads/when-to-use-a-hood.463691/ In the same vein, if I use my 24-105 for studio portraits, I fit the hood from a Canon 100-400 that fits straight on and works optimally towards the long end.

And yes, Sigma provides a crop-format lens hood extension with a few of their lenses.
 
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HoppyUK said:
And yes, Sigma provides a crop-format lens hood extension with a few of their lenses.
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I used to have a few Sigma lenses and I'm pretty sure it was one of those that came with two lens hoods, still can't remember which lens it was though.
 
My Sigma 105mm Macro came with two hoods, the FF hood and the crop extension. Oddly, I'd have thought the crop camera would require a smaller hood (as the corners are out of the frame) rather than a larger (extended) hood?
 
woof woof said:
I used to have a few Sigma lenses and I'm pretty sure it was one of those that came with two lens hoods, still can't remember which lens it was though.
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85mm 1.4 used to come with two or an extension, I can't remember which. Pretty sure they did that with a 70/200 as well but can't remember which.
 
gad-westy said:
85mm 1.4 used to come with two or an extension, I can't remember which. Pretty sure they did that with a 70/200 as well but can't remember which.
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You might be right. I had an 85mm f1.4 and that could have been the one, as far as I remember it came with two proper hoods not just an extension piece.
 
odd jim said:
My Sigma 105mm Macro came with two hoods, the FF hood and the crop extension. Oddly, I'd have thought the crop camera would require a smaller hood (as the corners are out of the frame) rather than a larger (extended) hood?
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Longer of the same diameter is the same effect as shorter of a narrower diameter...
 
sk66 said:
Longer of the same diameter is the same effect as shorter of a narrower diameter...
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If it's the same, the normal hood should suffice though surely?
 
With the Canon 17-40L, it comes with the EW-83E lens hood (which is the full frame hood designed for the lens) but on a crop sensor like my 7D, I've found that the EW-83J (designed for the EF-S 17-55) actually works better in terms of reducing potential flare etc. - and there's no traces of vignetting at the wide end of things. It also looks a little less like you've stuck a black dinner plate on the front of your lens.
 
TheBigYin said:
With the Canon 17-40L, it comes with the EW-83E lens hood (which is the full frame hood designed for the lens) but on a crop sensor like my 7D, I've found that the EW-83J (designed for the EF-S 17-55) actually works better in terms of reducing potential flare etc. - and there's no traces of vignetting at the wide end of things. It also looks a little less like you've stuck a black dinner plate on the front of your lens.
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Yes, you can swap some lens hoods around and if the lens is the same brand and same filter size, it will probably fit. But the actual size and shape are critical if you're trying to get optimum shading. Check it by shooting something like a clear sky at closest focus and lowest f/number, and compare images with and without. When it's close to optimum, any darkening will be very subtle and may disappear at higher f/numbers.
 
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odd jim said:
If it's the same, the normal hood should suffice though surely?
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Suffice? Usually... I've never worried about it. But it's about shading the effective FOV.
Make "tubes" with your hands and put one in front of your eye, then stack the other in front to make a longer tube. The FOV will be restricted more with the longer tube, by about 1/2. It's the same principle used with focusing lights, grids, snoots, etc, etc.
 
OMG I will never be able to take another photo worrying over whether I have the right lens hood fitted. :headbang::headbang::headbang::rolleyes:
 
chris malcolm said:
A full frame lens will be supplied with a lens hood appropriate to the angle of view of the lens on a full frame camera body. A crop sensor camera body using the same lens will have a narrower field of view. Consequently there could be a light source within the angle of view of the lens hood, but outside the angle of view of the sensor. That would cause flare and veiling in the image which would be removed if the lens were fitted with a longer or narrower lens hood with the appropriate angle of view for the crop sensor. The question is how much? Does the use of too wide a lens hood cause enough of a hit in image quality in enough cases to matter?

I note too that the expensive lens hoods which sometimes come with expensive lenses are sometimes very much blacker inside than the black plastic used in cheap lens hoods. That means for example that patches of the lens hood which are illuminated by the sun will reflect less light into the lens than the rather light black of the usual self-coloured black plastic.

Are we crop sensor camera users taking a significant hit in image quality by not changing the lens hoods on our full frame lenses?
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Hi, but not always. Take the ZEISS Planar 2/50 ZM for Leica M. It has the same ZEISS hood as the ZEISS Biogon 2/35. Both are for Leica M mount ("FF").

And the LEICA Summarit 2,5/50 and the LEICA Summarit 2,5/35 share the same hood.

You are right, of course. Each FL requires its own hood - theoretically. However, in real life, it must be difficult to see any differences.

LEICA and ZEISS would be happy to sell special hoods if there were ... ---

(P.S.: Some more: There is a ZEISS hood for a lens 4,5 / 21 and 2,8 / 25. Another one : 2,8 / 25 and 2,8 / 28.

And finally a LEICA (LEITZ) hood for a 4/90 , 2,8/90 , 4,5/135.

This is all I found in my cupboard ... --- )
 
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I carry an A4 sheet of black board hinged in the middle to use as a French flag if necessary. TBH, I can't remember the last time I used it for that (although Mrs Nod did use it a year or 2 ago as a fan!!!)
 
Few lens hoods are made with no leeway around around the field of view.
Most lens hoods used in the cine world and for large format cameras with movements are of the bellows type that are fully adjustable. Lens hoods for zoom lenses usually cover the widest setting and are not adjustable.

The matting of the interior surface of a lens hood varies considerably and is rarely optimal.. flock lined hoods are now rare.
Those with a narrow front but open out to form a larger internal black cavity are far less prone to internal reflections.
The common funnel like hoods are far less efficient.
 
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horse.collier said:
very helpful, dont you think? You are one of the reasons i rarely visit here.
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Looks like you haven't visited since 2017 and with only 34 posts since you joined in 2015 I don't think you've been missed.

Chat again in 2031?
 
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