Is there *ANY* UV/IR cut filter that will make BB Fuji GFX 50R fully usable in normal visible light?

[lukaszgryglicki]

I've recently bought Fuji GFX 50R - I *LOVE* it. Its colors and 400 dynamic range option are just amazing! I only have Fujinon GF 50/3.5 "pancake" and it is great. I also have M42->GFX and Nikon-F->GFX adapters and Nikon lenses work quite good with medium to very-very-very huge vignetting. My best finders are 55/1.2 AI which has almost no vignetting, same 135/2 AI-s and (wow) 20/3.5 Ai (heavy vingetting but not just cut-off circle as in almost all wide lenses) - that gives quite usable 16/2.8 equivalent on 44x33 mm sensor.

 

Now the question - I was thinking that I will convert it to BroadBand/FullSpectrum immediatelly - but I just figured out it will probably be my main camera now (again, I love it), so the question is - are there ANY UV/IR cut filters (can be very expensive, doesn't matter) that will revert it back to a normal usable visual only camera? (Can also be vis + UV because UV does not break anything when used with vis, its just too weak). I want to EFFECTIVELY cut off all IR in a way similar to original sensor IR cut-off works. S8612 is not good because it gives bluish hint - something like SEU that has straight edge cut-off (very sharp almost vertical) at 700 or 720 nm, or any other filter that will CUT all IR and *NO* visible.

 

Anybody have BB/FS Fuji GFX 50R and can share photos made with IR/UV cut filter? 

 

I just don't want to loose ability to use it 100% normally - and I don't mean Hoya UV/IR cut or Marumi UV/IR cut - they cut IR indeed, but not perfectly - I can see pink/red/violet hue on all photos made on my FS Nikons - they definitely cut some or even most IR, but not all - photos aren't correctly colored, autho white balance is no longer OK.

 

[colinbm]

Can you show us a graph of the Fuji GFX 50R Hot Mirror ?

[dabateman]

I don't own the 50R, but I do have the 50S. I also will most likely not convert it to full spectrum. 

From my tests it passes a bit of IR above 700nm and UV down to 370nm. So you don't want to cut off all IR or UV. So then filters like the BW486, a 2mm BG40 or Reeds new UVP IR cut filter may work for this sensor. 

The thing is you will not know until you test them on the converted sensor. 

 

Then if you don't like what you see, you might just need to pick up a second body for normal photography. 

[lukaszgryglicki]

Yeah 2nd body - when they cost that much is not an option. I don't have their IR/UV/hot mirror transmission cureve either.

I can do IR with it now - just need considerably more exposure - but when I tried UV (just once so far) way more exposore seemed to be needed, also EVF was almost black or loaded with HIGH iso noise.

 

[Andrea B.]

Congratulations on your purchase. Łukasz !!!  

It will be very interesting & exciting to see some Fuji GFX 50R photos.

Perhaps you can start a review topic and add to it as you go along?

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If Fuji will tell you the kind of uv/ir-cut glass used for filtration in the GFX 50,

then you can buy that and use it to ensure accurate Visible color.

Otherwise, the method below will ensure accurate visible color for a converted camera.

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As far as we know now, in May 2022, the way to ensure good, accurate visible color in a converted camera requires the following:

 

Tools:

 

1. good UV/IR cut filter

One good example currently is the Kolari Vision UV/IR cut filter. LINK

I think that UV should be cut in certain Visible scenes because of the scattering effects. For example, any landscape of medium to long distance.

2. white standard

3. color checker card

One good example is the Color Checker Passport which has both 2 and 3. LINK

For a white standard, PTFE or Spectralon are also good choices and can also be used for non-Visible work.

4. converter software which can make or accept camera color profiles from a color checker card.

I am familiar with using Photo Ninja for this. Tutorial Link: LINK

But other software can also make such profiles including the Color Checker Passport software. 

However you make your color profile, it needs to be available to the converter app, so that may limit your converter app choices.

 

Shoot:

 

1. Set an in-camera white balance against the white standard.

2. Make a raw photograph of both the white standard and the color checker card.

3. Proceed with the photography of the scene or subject.

 

Process:

 

 

1. In the converter app, test the in-camera white balance measurement by using the white balance tool on the photo of the white standard.

Not all cameras measure in-camera white balance accurately under filters.

However, inaccurate in-camera measurements rarely happen in Visible work. 

2. Store the WB measurement just tested for as a preset for possible use directly on a photo and/or for use when making a camera color profile.

3. Make a color camera profile off of the CC Passport photo and store it.

Such profiles correct the color for the specific shooting event based on:

camera, lens, filter, ambient light temperature, flash light (if used) and amount of illumination from all sources. 

4. Bring a file into the converter and apply the white balance preset and/or the color correction profile. 

If the color profile you made contains the white balance information, then you can skip the WB preset.

5. Continue processing the photo according to your usual methods.

 

This looks like a lot of work but I have not found it so after the initial learning curve is over.

 

 

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I should probably create a new topic for this mini-tutorial.

Suggestions, corrections, comments welcomed.

[lukaszgryglicki]

I would really like to help with that tutorial but currently I'm rather going to skip the converions - camera is too expensive and my only one digital MF. But I'm considerfing this in the future - I'll ask Fuji what they use for UV/IR cut and maybe for some transmission curve(s)?

 

[Andrea B.]

Given that you are a Fuji GFX 50R owner, Fuji might be more willing to answer your questions about its internal filtration specifications? 

 

Even though your GFX will remain unconverted for now, please do show us a photo or two from it sometime. 

 

[lukaszgryglicki]

Here you go - the one with very very heavy vingetting is from Nikkor 20/3.5 Ai (this is ~ 16/2.8 equivalent in 44x33 sensor). Other wide angle lenses are much worse, teles are better - 135/2 Ai-S seems to have no vingetting on this sensor and seems to be IDEAL portrait lens (~ 117/1.6 equivalent).

[Andy Perrin]

Fantastic photos. 

[lukaszgryglicki]

Thanks, a few more...

 

[dabateman]

Please let us know if you do get a response back from fujifilm. 

I would like to know. 

It kind of acts like a BG type of glass. Like one of the medical grade 61ish numbers.

[Andrea B.]

Those photos are looking good !!

Thank you for showing them to us. I would like to rent that camera sometime. I have never shot medium format. 

[dabateman]

Well depth of field is narrow, but this sensor seems to soak up light.

I haven't been able to under exposure like with this camera and still get incredible photos. 

The lenses I use are the 35-70mm fuji kit, Canon 40mm f2.8 stm,  Canon 50mm f1.8 stm,  Tamron sp 85mm f1.8,  Nikon 60mm f2.8 D macro,  Canon 100-400mm II with back baffle pulled out and Sigma 180mm f2.8 macro.  All fully cover the sensor. 

My Tamron adaptall 28mm f2.5 also fully covers, but I haven't used it much. I like the autofocus lenses.

The El 80mm and 105mm f5.6 lenses and my Pentacon 6 lenses also obviously fully cover the sensor. 

[lukaszgryglicki]

Forgot to say, most photos (excluding those with heavy vingetting) are with my only GFX lens so far - then pancake one 50/3.5 GF. Lenses for this format are prohibitely expensive, I *think* I'll buy 45-100/4 OIS (mainly because of its OIS that many sources say is very good) and 23/4 (that gives me wide and normal zoom - slightly tele), maybe 80/1.7 (for speed) or I'll wait for 55/1.7 (normal to slightly wide very fast).

[Andy Perrin]

Lovely colors and birds with real personality.

[lukaszgryglicki]

Thanks!

 

[JMC]

Lukas, not sure if you have seen this thread - https://www.ultravioletphotography.com/content/index.php?/topic/2758-eos-5ds-r-sensor-filter-transmission-measurement/#comment-21077

 

The chances are that the filter pack in your Fuji GFX is made up from two filters - a BG type glass and UV/IR cut filter - as most seem to be like that these days. Finding one single filter which gives the same shaped curve will not be easy and would probably need to be custom made. I know it adds more layers, and more complexity (and vignetting), but have you considered using two filters - a UV/IR cut and a BG type glass? That'll probably get you as close as you can to the original setup.

[lukaszgryglicki]

Just read this, I'm still not decided to convert my GFX 50R - I'm afraid it will become much less usable for normal photos, and it was too expensive to do this...

[Doug A]

Congratulations on the new medium format camera @lukaszgryglicki. Your images look really good. The sensor is amazing. It allows major underexposed shadow areas to be lifted in post processing.

 

I have considered getting the Pentax 645Z (same basic Sony sensor) converted. Like you, I haven't due to cost and other factors. Biggest worry is lenses. Looking at 35mm lenses, only about half I've tried work well for IR. Many have hotspots. Out of thousands of 35mm lenses, most of the "accidental" UV lenses are old designs. Medium format doesn't have 1000's of old lenses to pick from. The MF Fuji mirrorless allows using 35mm lenses. But, how many of the UV capable ones will fill the frame, without major vignetting? 

 

There are a few Fuji MF IR shooters in the DPreview forum. Not sure if any have converted a camera to UV. Poster Jim Kasson might know. He does lots of IR with the Fuji and provides lots of indepth camera testing.

 

Thanks for sharing,

Doug A

[lukaszgryglicki]

Many Nikkor lenses conver 44x33 without vignetting... examples:

- Nikkor 50/1.8 AI-s. (Japanise version, close focus 45cm).

- Nikkor 135/2 AI-s.

- Nikkor 85/1.4 AF-D.

 

Generally chances are bigger with longer lenses >= 50mm, shorter lenses usually vignette very heavy. Nikkor 20/3.5 AI-s works if you choose 6x7 crop. 35/1.4 AI-s (thorium) works 1:1. Nikkor 300/2.8 is said to cover even 6x9 format (with barrel mod), when using 300/2.8 without any mod there is no slightest vignetting at any aperture.

 

 

But you can run Pentax 645-A and pentax 67 (all lenses) even with T&S and/or macro-extensions conversions.

[Doug A]

@lukaszgryglickiI agree that many 35mm lenses cover the crop medium format. But, how many of those lenses are also good for IR and especially UV?  Are there any "accidental UV" wide-angles that cover medium format? A great sensor is useless without lenses that pass UV. Some of the Fuji GFX lenses are great for IR. UV is the tough one.

 

Remember how much effort was involved getting UV lenses for the Nikon. Medium format is a whole different level of difficulty. Wish it weren't true.

Thanks,

Doug A

[dabateman]

Doug,

The EL 80mm f5.6 and the El 105mm f5.6 Nikkor lenses both full cover the gfx sensor.  I know as I have them and they work.

My Steinheil 50mm f2.8 lenses doesn't fully cover,  but I wouldn't use that anyway. 

The Canon 40mm f2.8 stm lens fully covers and can be used with AF and is good for UV. The Stm Canon 50mm f1.8 is okish for UV, but also fully covers.

The Tamron 17mm f3.5 adaptall doesn't fully cover.

My igoriginal 35mm f3.5 lens also doesn't fully cover. 

My UAT I only tested at macro distance,  which I typically photograph at and if fully covers. But I didn't test infinity. 

So you have canon AF 40mm (equivalent 32mm), 50mm (equivalent 40mm), with Nikkor EL 80mm (equivalent 64mm), and 105mm (equivalent 84mm) lenses fully covering the Gfx sensor. My Tamron adaptall 28mm f2.5 lens fully covers,  but its horrible for UV photography. 

 

My home made 75mm fused silica element in a Canon 50mm f1.8 ii lens also fully covers. As do some other single element lenses. But thats not a surprise.  The El 80mm and El105mm mounted in a canon 50mm macro or ii AF lens tube vignettes fairly strong.

 

I haven't tested my mirror objectives (15x or 40x), but they might cover. Also haven't tested my Leitz 50mm macro lens, but it should cover.

 

The Nikon 105mm f2.8 AF-D macro has had vignetteing at 1:1, but fully covers from 1:2 to infinity.  This lens is surprisingly good for UV. I am not sure if the UV Nikon would act the same.

The Nikon 60mm f2.8 AF-D macro fully covers,  but I never tested it for UV. The Quantaray F-mount 24mm f2.8 macro is okish for UV and fully covers at macro distance,  but not at infinity. 

 

[Doug A]

@dabateman thanks for the nice run down of "accidental UV" lens options. Not surprised the two EL-NIKKORs work, since they were designed for even larger formats. Basically, we know of one suitable wideangle lens. Slim pickens, considering the price of the camera being modified. Longer focal length users have more choices. 

 

I need to try the unmodified Pentax 645Z and EL-NIKKOR 80 for UV. Interested to know if the UAT is vignette free thru the complete focus range.

 

Thanks,

Doug A