Wanted: Hoya R72 infra red filter (58, 72 or 77 mm)

The Hoya R72, as I understand it, is just barely an IR filter.

You might want something that doesn't let in as much light. The
highest that some use even kills the 'white effect' in trees, which I
think some like.

 

Who has such a filter for me?
Preferably 77 mm, but a 72 or 58 mm is also welcome.
Of course the filter must be in good shape.

Thanks in advance, Anita Riemersma

 

The R72, having a 720nm cutoff, is intended to be a true IR filter,
but like all such filters, there will always be a residual "leak" of
deep red at the toe of the response curve. The R72 is often a
favorite among IR photographers because its exposure factor is
considerably less than that of the deeper types (e.g. the R90), while
the effect produced is nearly the same. Many cameras that have the
most aggressive IR blocking filters can only be used with the R72,
such as the Olympus E20 and a few others. I've got both R72 and R90
filters in various sizes, but the R72 is the one that's always in my
kit. The 77mm is about $145 from 47th St Photo (where I got mine
recently), but lots of these both new & used show up on eBay. I'd
recommend you go for the biggest one you can, since a large one can be
easily adapted down to your smaller lenses.

You might also be interested in the other end of the spectrum as well.
UV pass filters are available that allow photography in the near UV
range, albeit to a limited degree with digitals.

 

Wrong. The R72 midpoint is 720nm. i.e., half the spectrum let in is above
720nm, and half is below. It pretty much completely cuts off at about 680nm,
which is in to the deep red. That's why you can see some red through it.

That said, it's still a good IR filter for most purposes, and much brighter
than true IR filters.

 

Please clarify what you mean by claiming I was "wrong" -- isn't that
exactly what I said? I never denied that the R72 had a 720nm cutoff,
in fact that's exactly what I said. The visible spectrum is generally
regarded as ending at 700nm. I assumed everyone (but not you
evidently) understood that a "cutoff" level in nm is the point where
the filter's attenuation (or transmission) is at half it's pass
characteristic. I also stated that the "toe" of its transmittance
falls within the visible deep red.

The Hoya R72 has similar pass characteristics as 89B, see:
www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM#FIL
and for response charts:
http://www.photo.net/photo/edscott/ir000020.htm

 

Yeah, I know. But it's misleading to say the cutoff is 720nm. Most people
would interpret that as light being "cut off" at 720nm, but it's really not.
Only half the light is.

 

There are is a lot of misleading terminology commonly used regarding
"Near Infrared" photography using consumer digital cameras. Most people
incorrectly call it infrared (IR), when it's actually "Near Infrared".

True Infrared (IR) like you see the Police choppers use to locate
suspects by their body heat costs well over $10,000 USD. Most digital &
video cameras are insensitive to anything above 1,100 to 1,200 nm even with
the internal infrared cut filter removed.

For digital still photography I almost always use my HOYA R72 because it
allows for reasonably fast shutter speeds with most of my cameras. True it
does let a little of the deepest red though but I have not found this
disadvantageous to the intended NIR look.

If you want or need to block out all visible light you can spend more &
buy a B+W 093 or a Heliopan RG 1000 which as their name suggest, cut off 50%
at 930nm & 1000nm respectively. Although I have all 3 filters, I have found
that the HOYA R72 meets 95% of my needs. It's at least a good relatively
inexpensive filter to try 1st because you may be quite pleased with it.

Chances are that you won't need anything stronger & thus much more
costly & both of these other filters will require increased exposure times.

Also the little bit of deep red that gets through the HOYA R72 will
usually be just enough to provide you with a bright enough image on the LCD
display so that you can frame you shot with it.

Respectfully, DHB

 

To add fuel to the fire, Heliopan makes several filters for IR
photography. Specifically: RG 610, RG 630, RG 645, RG 665, RG 695 (89B),
RG 715 (88A), RG 9, RG 780 (87), RG 830 (87C), RG 850 and RG 1000. Of
course you can also try Yellow 12, Orange 22, Red 25 or green 13 for
false color work with IR color film (they may or may not be suitable for
IR digital).

 

Having a variety of IR filters with differing cutoff wavelengths
allows for some clever false-color effects, since it is possible to
subtract one image from another in Photoshop. Thus you could create a
whole new R-G-B spectrum from the subracted spectral content. I tried
this, but none of the digitals in my collection were sufficiently
sensitive below about 800nm to really play with this.

 

I think your interpretation of "cutoff" is a bit misleading to many.
To clarify this, with a theoretically excellent filter you could have
99 percent of the desired IR spectrum passed by the filter, and the
falloff to zero could exist over the remaining 1 percent. In this
case, the cutoff point would be defined at the 99.5 percent point, or
where the attenuation of the desired passband falls to half as it
drops to zero. For this reason I fail to see your idea that "only
half the light" is being cut off, except for a very unusual case.

 

Hi,

It seems to me that you have quite a lot of experience in digital IR
or near IR photography.
Because I'm thinking of buying a Hoya R72 filter for my Canon 10D
camera and start experimenting (never did IR photography on film
because of all the hassle), can you please tell me some more.

I have f.i. following questions:
- do you have experiences with this lens-filter combination? Does it
work well?
- what will be the approx. exposure time for "normal" pictures made
this way?
- after making the pictures, do you need to do some adjustments in
Photoshop afterwards (if so, what and how?) or do you get IR or near
IR like pictures right away?
- will different lenses give different results as far as quality of
the picture is concerned (FYI: I only use L lenses)? In other words:
is f.i. a 28-70 lens better/worse than the 20-35 mm?
- do you need to cover the viewfinder while making the picture to
prevent extra light coming in?
- any other hints and tips?

Thanks for your help, Anita Riemersma

 

It seems to me that you have quite a lot of experience in digital IR

What happens if you just use the Red channel and convert it to greyscale?

Wouldn't be perfect near-IR photography, but it wouldn't cost anything
either....

David

 

Apart from darkened skies, the effects from using the red channel
(alone) do not resemble those obtained with an actual IR filter. In
fact in many cases when using an IR filter the red channel may be
deliberately excluded because of red leak-through. Exaggerated
veins, black eyeballs, white foliage and extreme penetration of haze
are characteristic of "true" IR photography.

I find the most useful lenses to be wideangle types, since they often
tend to enhance the surreal quality of IR photography. Also you need
to experiment with lens stops with any lens, since with IR the "sweet
zone" of the lens may not agree with that experienced in the visual
spectrum. Unfortunately many of the newer plastic crappo lenses no
longer have IR markings for infinity, so you may need to create your
own mark. It should be understood that filter factors (for the same
filter) vary widely, depending on each camera's CCD characteristic.
Some are essentially IR "dead," such as the Oly E20 and a couple
others. For these, even an R72 may require long exposure times.

I suspect your 10D may have similar IR response to my D100, not real
hot but useful with the R72. The 10D has an agressive "hot mirror"
filter over its CCD, so exposure times are likely to be long,
typically on the order of seconds. The D30 would be a much better
choice, having a weaker internal filter.

 

I think he was saying that the center of the band was at 720nm. From
the links you gave, it seems that you were right that the edge of the
band (50% transmission) is at 720.

 

http://www.wrotniak.net/photo/infrared/

 

Top-postin' Chris Quinn wrote in part:

Wherein the DSC-F717 is dissed yet again, I guess because it's a Sony.
Yes, it's crippled by Sony's paranoid lawyers to f2 and 1/60 (fastest)
in "nightshot" mode. But it's a lot easier to deal with that than to
always settle for long exposures and letting the IR-pass filter compete
with the IR-cut hot mirror.

Reminds me of the Stephen Wright joke about putting a humidifier and a
dehumidifier in the same room and watching them fight it out to the death.

I've said before that the F717 is my last Sony, but meanwhile I'm taking
advantage of what it can do. This is one feature I've enjoyed.


Corry

 

Which lens? The 10D can take many lenses.

I've used 3 different digicams for IR work. In full sun, they all required
exposures in the ballpark of 0.5 - 1 second, using the lowest ISO setting
(and largest aperature). Older cameras seem to be more sensitive in general,
but they also had slower lenses. So, it sort of balances out.

My C5050 can take IR pictures indoors during the daytime, but the exposure
needed is many seconds.

Depends on the camera, but usually IR pictures on quite low contrast, so
boosting the contrast often helps. Also, on some cameras, the image gets
some horrible color cast, so converting to black & white (or doing it in
camera) is often a good idea. Although, I really liked the slight red leak
on one of my old cameras (d460).

 

Have you, or anybody else tried illuminating a shot with an IR lamp?
Anybody know of a cheap one I could try doing this with?

I'm waiting for my R72 filter to arrive.

 

In message <X0BNb.8682$>,
Unclaimed Mysteries

Sounds like a very roundabout way to generate lots of heat.
--

 

Anita Riemersma,
in addition to answering your questions, here
is a very good web site with some very good information about near infrared
photography:

http://www.cliffshade.com/dpfwiw/ir.htm

You hit me with quite a few questions & I will do my best to answer them
because I know what it feels like to become interested in something new &
want to get informed ASAP.

Disclaimer: Sorry I'm no expert in near digital photography but I have
learned & taken lot's of NIR pictures over the past 2+ years beginning with
a humble 1MP Kodak DC215 digital camera with a HOYA R72 filter.

<Q1> "Do you have experiences with this lens-filter combination?"
<A1> Don't know which lens/combination your referring to here? If you
are referring to DSLR lens & HOYA R72 combinations, my DSLR (Digital
Rebel/300D) NIR experience is thus far limited & the Canon 10D or 300D is
not the best choice for NIR photography because they have a very good
quality infrared cut (IRC) filter. IRC filters greatly reduce the amount of
NIR & IR from reaching & adversely effecting visible light pictures produced
by the sensor but in so doing also greatly reduces NIR sensitivity of the
sensor.

<Q2> "Does it work well?"
<A2> Due to the relative insensitivity with either camera (10D/300D),
exposures will need to be long or ISO relatively high.

<Q3 > "What will be the approx. exposure time for "normal" pictures made
this way?"
<A3> Thus far all of my NIR pictures taken with my Digital Rebel/300D
has been done with my Canon 50mm f1.8 II lens with well exposed pictures
taken at an aperture of f5.6 & shutter speeds ranging between 1 sec. to 3
sec. with ISO settings from 200 to 800.

<Q4> "After making the pictures, do you need to do some adjustments in
Photoshop afterwards (if so, what and how?) or do you get IR or near IR like
pictures right away?"
<A4> Editing the resulting image has a lot to due with personal
preference. As for me I like the more conventional B&W effect over the
"false color" pictures that will be produced unless your shooting in RAW
mode. So you only need to convert the images to grayscale (0 color
saturation). Any other adjustment are subjective. Noise reduction software
can help if your pictures are noisy which will depend on ISO, shutter speed
& how hot the sensor gets as noise increases a bit in higher temperatures.
Always try to keep your camera out of prolonged direct sun.

<Q5> "Will different lenses give different results as far as quality of
the picture is concerned (FYI: I only use L lenses)? In other words: is f.i.
a 28-70 lens better/worse than the 20-35 mm?"
<A5> Don't own an "L" lens yet so I can't answer this 1 from experience.
However, I'd expect that a faster, higher quality lens should only improve
your results. Just remember than your not likely to want to take pictures
with your lens wide open because the resulting DOF is likely to be far less
than you might like, hence my use of f5.6 on my 50mm instead of f1.8.

<Q6> "Do you need to cover the viewfinder while making the picture to
prevent extra light coming in?"
<A7> Usually this in not necessary if you stand between the viewfinder
& the sun as I always try to do when taking any daytime exposure requiring a
tripod. If your exposure is going to be longer than 5 sec. or you can't
fully block stay light from getting in, than yes I would use the supplied
rubber eyepiece viewfinder cover which should be on your neck strap to block
it.

<Q8> Any other hints and tips?
<A8> Search the Internet, there are lot's of good informational sites
that you can learn a lot from. Give strong consideration to using a good
quality 4MP digicam because since they have such a small lens & sensor that
their DOF is usually very wide. People call them "flat" because the DOF
tends to extend from just a few feet to infinity but for NIR this is amost
always an advantage. Also these less expensive digital cameras "usually"
have less effective infrared cut (IRC) filters, thus making thier sensors
more NIR sensitive. This means that faster shutter speeds / lower ISO
settings can be easily obtained.

"Thanks for your help, Anita Riemersma"

Hopefully somthing I have shared here does in fact prove helpful to you
or others interested in NIR photography.

Respectfully, DHB