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Canon 40mm f2.8 STM lens

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#1 SteveE

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Posted 03 May 2021 - 00:12

The Canon 40mm f2.8 STM lens is listed as UV capable. While perusing reviews of this lens I saw in the Ken Rockwell review referenced below that Canon recommends not using more than one filter so as to not damage the the innards of the focus mechanism. Has anybody here had success using it with a dual filter stack such as a U360 2mm and S8612 2mm?

https://www.kenrockw...es/40mm-stm.htm
- Steve

#2 colinbm

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Posted 03 May 2021 - 02:31

I have the Canon 40mm pancake lens & I have used it with stacked filters many times with no issues.
I didn't know this could be a problem ?
The only problem I have with this lens is I like it so much, that it doesn't want to come off the full spectrum, Sigma fp, full frame camera.
I am surprised at how wide 40mm is on a full frame sensor.

#3 Andy Perrin

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Posted 03 May 2021 - 02:36

I have heard varying opinions on Ken Rockwell's reviews...

Edited by Andy Perrin, 03 May 2021 - 02:36.


#4 SteveE

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Posted 03 May 2021 - 03:36

I just found the manual for it on line and it contains, in an exclamation marked box, "Only one filter may be attached"
I am relieved to hear that it works with two filters as I bought a copy from KEH before I discovered this notation.
- Steve

#5 dabateman

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Posted 03 May 2021 - 03:56

I have even used mine with a 52mm to 77mm step up ring and two 2mm filters at that size. A BG39 and ZWB2 each 77mm.

The concern maybe that the front helicoid with filter threads is plastic. I can't remember and it might not do so well in autofocus speed with too much weight. Or it maybe Canon being overly cautious as users with too many filters might be sloppy.

Just don't knock it around or hit the filters on something and you should be ok.

A bigger concern might be the filter you use compared to the lens. If the focus motor breaks. Just buy a second one. I got mine used for $80. Much cheaper than most of the filters I put on it.


#6 colinbm

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Posted 03 May 2021 - 04:08

Yes it is a plastic filter thread, so be careful when screwing on the filter/s.
Perhaps the big Cokin square filters may be too much weight ?

#7 colinbm

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Posted 03 May 2021 - 06:49

Thanks Dave, for the tip on this lens, it just keeps getting better & better....

The Canon 40mm pancake is such a versatile lens for us on UVP, especially now with a full frame, full spectrum camera.
The only 40mm auto lens for 365nm & above photography. Great from 1ft or 0.3 m to infinity. Close for UV flowers & wide for IR landscapes.

Now with the reverse lens adapter it is a 1:1 macro with auto with 52mm filter rings.
What more could a guy want with the Sigma fp full spectrum camera, I am in heaven......

#8 UlfW

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Posted 03 May 2021 - 07:11

View PostAndy Perrin, on 03 May 2021 - 02:36, said:

I have heard varying opinions on Ken Rockwell's reviews...
The net is full of opinions, also in reviews.
When reading reviews you must be ready to filter and analyse the content as it often is biased.

In this case Ken's review, cites some text from the lens's user manual.

My opinion about the 2-filter problem and solution is identical with what dabateman is writing above.
In general it is a good idea to be careful with the equipment and avoid banging it around too much.

One problem with plastic threads is if the filter is not correctly aligned when changing filters, the plastic threads will lose the battle and get destroyed.
A thin empty filter ring would give the lens a metal filter thread.

I normally use the Manfrotto's Xume magnetic filter holder system for quick and easy filter changes. A Xume-pair extends further than a single empty filter ring.
I cannot see any vignetting with the EF 40 STM on a full frame sensor camera when I have a dual filter stack mounted (including a second Xume holder pair).

I know that people who like to bang their equipment around think that the Xume system does not keep the filters on the lens safe enough.
My opinion is that the Xume works well, but then I try to be a bit careful with my filters and lenses.

Edited by UlfW, 06 May 2021 - 11:36.

Ulf Wilhelmson
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#9 Andrea B.

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Posted 03 May 2021 - 15:41

Editor's Note: I'm going to add a comment to the lens review of this Canon 40/2.8 STM about the plastic filter thread.
Andrea G. Blum
Often found hanging out with flowers & bees.

#10 SteveE

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Posted 03 May 2021 - 16:26

I have found that Tiffen filters mount the filter using a ring which can be unscrewed with a lens spanner to make a thread protector. The Hoya filters that I tried this with have the filter crimped into the ring, necessitating breaking the glass to remove the filter.

Edited by SteveE, 03 May 2021 - 16:44.

- Steve

#11 SteveE

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Posted 03 May 2021 - 16:29

Quote

I'm going to add a comment to the lens review of this Canon 40/2.8 STM about the plastic filter thread.

Same for the 24mm f2.8 STM EF-S (APS-C)
- Steve

#12 Andrea B.

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Posted 03 May 2021 - 17:23

Got it. Thank you. :smile:
Andrea G. Blum
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#13 colinbm

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Posted 06 May 2021 - 11:14

I have the reverse lens with electric contact to control the lens & used it with the Canon 40mm pancake lens & I can see no problems with this setup & the plastic 52mm filter ring is now supporting the lens & the electric adapter on the outboard end.
Just the usual care in threading the adaptor on the plastic 52mm filter end & the usual care in handling the lens & camera & I can see no problems, there is not much weight involved with this lens, everything is pretty light weight.