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Lens hood type

Equipment
Camera Lens Astrophotography •7 replies•113 views
framoro avatar
framoro avatar
Hi everybody,
Is it a problem to use “petal-like” lens hoods for camera lens astrophotography?
is it necessary to use a cylindrical one?
Looking for your expert advice.
CS
Richard Rice avatar
Richard Rice avatar
I don’t believe that it is essential and depending on how wide angle the lens is a cylindrical hood simply wouldn’t work. However in my experience cylindrical hoods make using a bahtinov mask for focusing and the taking of flats for stacking easier. I’d say they probably make dew heaters more effective too.
Concise
JD avatar
JD avatar
In my experience the cylindrical hoods (in combo with a dew heater strip) do a much better job preventing dew - but that said - it depends on the geometry of the lens.  I've found that when using the wide-angle lenses I have that come with the petal style lens hoods - if I use a cylindrical hood, I have vignetting problems.  It is a tricky balance, because if I use the petal style lens hood - then dew is a really difficult problem.

I would say you should experiment with different configurations.  There are fairly inexpensive sources for different size/style lens hoods, so I don't think it would break the bank to do so.   Good luck!
JD
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OriginalJoie avatar
OriginalJoie avatar
I've 2 Rokinon/Samyang lenses that have petal style lens hoods and I have no problems with dew wrapping the dew heater around the end of the lens just behind the lens hood.

  On my lenses this does put the dew heater on the focus ring though so one must either tape focus or make sure that the cord for the dew heater isn't pulling on it causing focus to creep.

  As for the Bhatinov Mask I have been able to adjust the 3 holding screws so they fit inside the petals.  it's more prone to falling out if you bump it but if you bump it that hard the mask falling off is the least of your worries.
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framoro avatar
framoro avatar
Richard, JD,

Thanks for your comments I will try!

Do you have experience with light pollution with the one or the other lens hood? Would the type of hood have an impact?

CS
framoro avatar
framoro avatar
Thank you OriginalJoie for your comments.
Richard Rice avatar
Richard Rice avatar
Do you have experience with light pollution with the one or the other lens hood? Would the type of hood have an impact?

I guess that depends on what you mean by LP. If you‘re talking about one of these back garden search lights which switches on every time a cat walks past it then you’ll probably need to get inventive with a clothes line or something similar to shield your gear irrespective of what lens hood you use. If you are referring to the kind of  light domes you see on the horizon, I don’t think the type of lens hood will make much difference. 
(I could be wrong please let me know if you find that I am).
framoro avatar
framoro avatar
Thanks Richard.
I'll do the experiments.
CS