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03-31-2023, 07:22 AM - 10 Likes   #1
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Two new and surprising magnetic filters from K&F CONCEPT

I’ve been a fan of K&F CONCEPT’s magnetic filter system ever since it came out. Magnetic filters truly changed the way I work when on hikes with non-photographers, or when traveling. Even magnetic lens caps are wonderful. Most of my lenses now have magnetic adapters. I’ve written about the system in the past here and here.

I was really curious when the company released two new elements to their system. Both are intriguing to say the least. Here’s my mini-review and comments.

The first is a variable ND filter (VND). It makes sense that it exists, but given that magnetic filters rotate freely, I wondered how it worked. The filter is this one: K&F Concept 67mm Magnetic Variable ND8-ND128(3-7 Stop) Lens Filters - Nano-X - KENTFAITH.



The short of it is that it ships with a lens adapter (the magnetic part which stays permanently on the lens) which has three recesses to lock the filter in place. Of course, the filter has bumps which match those recesses. So when you mount it, it locks and stays in place, so you can rotate the front of the filter to change the attenuation. Kind of like a magnetic bayonet, in a way.



However, I have a few magnetic rings already on my lenses, and I don’t want to purchase replacements with the recesses (plus I’m not sure they’re sold stand-alone). So I mounted the VND on a regular magnetic ring. The great news is that K&F CONCEPT tuned the VND’s friction very well. It’s entirely possible to adjust the attenuation without having the whole filter move. I was seriously surprised. It just works, and that’s the best news out of this for me.



If you spin too hard, it will slip of course, but I did not expect it to work at all.

The VND can also be stacked over other filters, which is one of the nice things about those magnetic filters. It’s the same thing as when using an adapter without the recesses. All the filters in this system have the same outer diameter, except for the VND which is bigger. You also cannot mount filters to the front of it; it should be the last step in your stack. The magnets are not oriented properly to mount anything towards the front, and the size isn't right.



The VND does not create a polarizing effect in images. I also did not observe the infamous X pattern which sometimes appears with wide angle lenses. My tests also show that, like other K&F CONCEPT filters I’ve used before, there is no sharpness degradation and no color cast when using them. That’s saying something: many high-profile brands do create those casts. These filters are, optically, the best I’ve used (and I've used a few different brands).

The VND covers ND8 through ND 128, a moderate range. It is stepless as can be expected. There are markings on two opposed sides, so regardless of the orientation, you see the scale.




The other new filter is a graduated ND filter (GND) reaching ND8. That one is, in a way, even more surprising. GNDs are normally squares or rectangles, and the transition can be adjusted precisely and at will via a big and complex mounting apparatus. This GND is a magnetic circle with the transition close to the center. I was curious to see how I could use it.



It turns out that the filter does force the user to compose with the filter. Transitions, horizon lines, etc, should be taken into account when using the filter. That doesn’t mean the horizon should be in the center, but that you need to think about your end result a bit more. One nice aspect of this filter is that it can so easily be rotated, it can serve with irregular scenery also, like this NASA building below.



While the VND filter is bigger than other K&F CONCEPT magnetic filters, the GND is the same size.




The GND ships with a kit, including an adapter ring, ND8/64/1000 regular ND filters, and a great case. This case is improved from what the company used to ship. It has a zipper, but also a magnetic flap which makes it quicker to reach inside. It also has a belt loop with velcro, and a metal loop to clip it somewhere.




So, long story short, I’ve been a fan of K&F CONCEPT’s filters for a while, and I truly love these new additions to their lineup. Both are optically better than what we ought to expect, both are easy to use, and both make it simpler and easier to include filters in my workflow.

I hope this was useful! Here are a few examples of the filters in use:

VND


VND


No filter

VND 16

VND 32

VND 64

VND 128


No filter

GND poorly oriented (intentionally)

GND well oriented (and not horizontal)


GND



Last edited by bdery; 04-04-2023 at 12:51 PM.
03-31-2023, 09:40 AM   #2
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Thanks for sharing this. Have you checked whether the magnets are enough to throw off the built-in compass of some cameras like the K-1 or OGPS-1 compass feature?
03-31-2023, 09:49 AM   #3
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QuoteOriginally posted by ProfessorBuzz Quote
Thanks for sharing this. Have you checked whether the magnets are enough to throw off the built-in compass of some cameras like the K-1 or OGPS-1 compass feature?
Great question. I wasn't that interested in these....until I saw this GND, so easy to rotate. Now, I'm interested.
03-31-2023, 09:53 AM   #4
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Interesting indeed!, the graduated ND is something I might consider. It is fixed and defines the composition somewhat but that is a lot better than nothing.

We really need Ricoh to put their finger out too on the in camera Grad ND menu option. Give us the option to buy the key, I have the firmware already.

03-31-2023, 10:17 AM   #5
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QuoteOriginally posted by ProfessorBuzz Quote
Have you checked whether the magnets are enough to throw off the built-in compass of some cameras like the K-1 or OGPS-1 compass feature?
I have not *specifically* tested that, but I have used the K-1's astrotracer with an adapter ring mounted, so I presume it has no impact.

QuoteOriginally posted by texandrews Quote
I wasn't that interested in these....until I saw this GND, so easy to rotate. Now, I'm interested.
Crazy easy indeed. Much better than anticipated. It's really smooth, but also with good friction and feedback. They nailed it.

QuoteOriginally posted by Kevin B123 Quote
the graduated ND is something I might consider. It is fixed and defines the composition somewhat but that is a lot better than nothing.
My thought exactly. As I've written before, these magnetic filters have reconciled me with filters. I had stopped using filters before, too complex when with other people (family, friends) who are simply not patient enough. With a wide angle lens and the GND, it's possible to recompose via cropping to correct composition constraints of the GND.

QuoteOriginally posted by Kevin B123 Quote
We really need Ricoh to put their finger out too on the in camera Grad ND menu option. Give us the option to buy the key, I have the firmware already.
I'd need to give this more thought, but I'm not sure I would like that. It would either be done via post-processing, something which can be done better via computer, or by playing with ISO at the sensor (analog) level, which would require some heavy lifting, and possibly a change to the camera's electronics.
03-31-2023, 11:41 AM   #6
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QuoteOriginally posted by bdery Quote
I'd need to give this more thought, but I'm not sure I would like that. It would either be done via post-processing, something which can be done better via computer, or by playing with ISO at the sensor (analog) level, which would require some heavy lifting, and possibly a change to the camera's electronics.
I'm sure that many people would use software as it's the normal way currently, it's just that I'm a bit reluctant to go that route and would rather have a single combined raw file to work on. Perhaps it's a bit limited in appeal but it's on offer and I want to try it out.

Last edited by Kevin B123; 04-01-2023 at 11:41 AM. Reason: typo
04-01-2023, 12:04 PM   #7
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QuoteOriginally posted by bdery Quote
The GND ships with a kit, including an adapter ring,
A question on the GND if I may.

I can buy the 62mm GDN filter on it's own and the sales blurb make no mention of needing an adapter.

Will the GND just screw onto the lens thread like a normal CPL? or does it come with the magnetic bit that screws onto the filter?

Thanks

04-02-2023, 03:46 AM   #8
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QuoteOriginally posted by Kevin B123 Quote
it's just that I'm a bit reluctant to go that route and would rather have a single combined raw file to work on.
You will have a single file to work on if you use Lightroom. Lightroom takes several DNG files and combines them to a single linear DNG file. It also does a good job aligning the input files so you can use this with the camera handheld.
04-03-2023, 05:30 AM   #9
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QuoteOriginally posted by Kevin B123 Quote
A question on the GND if I may.

I can buy the 62mm GDN filter on it's own and the sales blurb make no mention of needing an adapter.

Will the GND just screw onto the lens thread like a normal CPL? or does it come with the magnetic bit that screws onto the filter?
You can't screw the magnetic filters, they need a magnetic adapter ring which is "permanently" on the lens. That's one of the reasons the filters can be so thin. Can you share the link you found for just the GND?
04-03-2023, 09:36 AM   #10
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QuoteOriginally posted by bdery Quote
You can't screw the magnetic filters, they need a magnetic adapter ring which is "permanently" on the lens. That's one of the reasons the filters can be so thin. Can you share the link you found for just the GND?
This is a link to the one I wanted, it makes no mention of the magnetic mount as a separate piece so I guess it is a separate part of the GND and comes with it.


62mm HD Soft GND8 Lens Filter 3 Stop (0.9) Soft Graduated Neutral Density Filter - K&F Concept
04-04-2023, 12:57 PM - 1 Like   #11
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QuoteOriginally posted by Kevin B123 Quote
I'm sure that many people would use software as it's the normal way currently, it's just that I'm a bit reluctant to go that route and would rather have a single combined raw file to work on. Perhaps it's a bit limited in appeal but it's on offer and I want to try it out.
Agreed. Many people enjoy post-processing and that fine, but many people prefer the act of taking a picture (me included) and that's fine too.

QuoteOriginally posted by Kevin B123 Quote
This is a link to the one I wanted, it makes no mention of the magnetic mount as a separate piece so I guess it is a separate part of the GND and comes with it.
The link you provide is for a non-magnetic filter. These will screw on your lenses, like other filters since many decades. The magnetic line of filters are optically the same (at least, they bear the same labels) but come with two parts. Have a look here, this link includes several options including the GND + ND8 + ND64 + ND1000 + adapter ring. You screw the adapter ring on your lens, then swap the filters magnetically. The adapter ring can also accept any other magnetic filter from the brand, magnetic lens caps provided with some kits, and regular lens caps (which isn't the case with all brands of magnetic filters).
04-04-2023, 01:49 PM   #12
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QuoteOriginally posted by bdery Quote
The link you provide is for a non-magnetic filter. These will screw on your lenses, like other filters since many decades. The magnetic line of filters are optically the same (at least, they bear the same labels) but come with two parts. Have a look here, this link includes several options including the GND + ND8 + ND64 + ND1000 + adapter ring. You screw the adapter ring on your lens, then swap the filters magnetically. The adapter ring can also accept any other magnetic filter from the brand, magnetic lens caps provided with some kits, and regular lens caps (which isn't the case with all brands of magnetic filters).
Thanks!, I sort of thought I had the wrong one but didn't know the threaded type existed.
I'll follow the link and take a look.
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