[ntrao]

Hi Pentaxians,

Few months back, I acquired a M20mm f4 lens in very good condition without a lens hood. I ordered one metallic 49mm lens hood and it is vignetting very bad, literally not usable images with round circles. Then I understand, this lens require a wide angle hood and may be a square hood. Little search on the internet pointed me expensive $30 hoods, which I am not interested in buying. Is there any cheap alternate hood suggestions for the 20mm lens. Please help!

[pid]

did you try to combine two or three StepUpRings. You can get a set for under 10$.
First ring should be 49 to 55 mm and than 55 to 58 and 58 to 62. Should work.

[acoufap]

Hi Pentaxians,

Few months back, I acquired a M20mm f4 lens in very good condition without a lens hood. I ordered one metallic 49mm lens hood and it is vignetting very bad, literally not usable images with round circles. Then I understand, this lens require a wide angle hood and may be a square hood. Little search on the internet pointed me expensive $30 hoods, which I am not interested in buying. Is there any cheap alternate hood suggestions for the 20mm lens. Please help!

Which step-up rings to use depends on your sensor format. With an FF sensor you get a much wider field of view than with an APSC sensor.

On FF my M2.8/28 needs a step-up ring 49-67mm using a round JCC Metal Lens Hood. On APSC 62mm is sufficient.

Your M4/20 mm has a much wider field of view than my M28. So I guess 62mm on APSC is not sufficient.

Look here (a PF article) to get a notion about the field of view of lenses depending on FF vs. APSC and Focal Length.

[D1N0]

This is a picture of the original hood.


The m-20 is pretty much flare resistant so a hood isn't really necessary

[torashi]

Just use your hand to block the out of frame light sources, or you could buy one of those cheapo rubber collapsible hoods, project some light through the viewfinder and cut out what's "touched by the light". You should get a nice petal shaped hood. Or just cut out the one you have already, albeit if it's metallic, you're gonna need some kind of motor tool to do the job.
Doesn't matter if you're using FF or APS-C since by projecting through the whole optical system will yield your used FOV. One note: if your viewfinder isn't 100%, you need to cut a bit more. Live view can help with those finishing touches. Also, if you're gonna use filters, put them on before cutting the hood, or see if you can use them after the hood. Happy DIYing!


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[ntrao]

First ring should be 49 to 55 mm and than 55 to 58 and 58 to 62

I've 49-55 and 55-58, I should give a try then.

With an FF sensor you get a much wider field of view than with an APSC sensor.

I just acquired K1 and using M20 with a vented lens hood is giving problem.

Just use your hand to block the out of frame light sources, or you could buy one of those cheapo rubber collapsible hoods

Yes, but I cannot use my hand as this is a manual lens and it requires my other hand to adjust focus, mostly.. And yes, rubber collapsible hood is in my mind as a last option, if step-up rings solution doesn't work.

[D1N0]

Even the metal holding ring of a rubber hood displayed vignetting on my K-1, so I ended op using just a 49-52mm step up ring.

[pschlute]

I use a metal "wide angle hood" by b+w. it has a 58mm thread so I use a 49-58 step-up ring and it works fine. no real need to get a rectangular hood.

[ntrao]

Even the metal holding ring of a rubber hood displayed vignetting on my K-1

oh, it's no good. You certainly saved my few bucks. I have few combinations of metals lens step-up rings with 49, 55, 58, 60, 67mm. I will give a try tomorrow.

I use a metal "wide angle hood" by b+w

It looks like an expensive option.

[pschlute]

It looks like an expensive option.

Any make of hood will do.

A quick ebay search reveals a generic hood and step-up ring can be sourced for less than £10

Cheap as chips as we say over here.

[stevebrot]

I just acquired K1 and using M20 with a vented lens hood is giving problem.

FWIW, while vented hoods may look cool, they are intended for use on rangefinder cameras where a hood may intrude into the viewfinder. The "vents" serve as windows for the photographer to look through while framing. They don't affect which focal lengths a hood is good for.

As noted above, any hood at 20mm with a FF camera will have minimal depth and even a thick filter ring may cause vignette, hence the use of step-up rings as hoods. The nice thing is that step-up rings are cheap and a useful thing to have in the filter box. Good luck on finding something that works and please post back when you find a solution. Even better would be to post here and write a review of the M 20/4 for this site that includes your hood solution. I just noticed your M 20/4 review, so perhaps editing it to include your adventures in finding a hood would be good.


Steve

[stevebrot]

This is a picture of the original hood.


The m-20 is pretty much flare resistant so a hood isn't really necessary

Do you own this hood? If so, a review for this site would be helpful. The review for the M 20/4 erroneously suggests the PH-S49 (28/35mm), which would be adequate for APS-C, but not for 24x36mm FF and having a model number and review to point to would be nice.


Steve

[dms]

Not for FF, but efficient (and not very deep) on APSC is the Takumar (metal rectangular) 28 mm f/3.5 hood. I put some photo tape along the side however, so I don't unknowingly bump it/push it askew.

[torashi]

This is a picture of the original hood.


The m-20 is pretty much flare resistant so a hood isn't really necessary

It's quite a complex hood. It's an external clip on, so no metal ring over the lens's filter ring, and even then it has cut outs for the edges.

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[D1N0]

Do you own this hood?

Nope, There is a pic of it in one of the reviews