[adam]

When I first attached the R72 to my 18-55 kit lens last year, I was disappointed to find that the camera was not infra-red sensitive. However, with longer exposures, there was some evidence that some light was getting through, so I assumed that it was being exposed with the light in the visible spectrum that didn't get blocked, since the R72 does not cut out all the visible light.
I didn't try again.
On Saturday, at Kings Park, I took out the R72 again and put it on the 18-55, took some pictures, but when I came home, I found a hotspot in the centre (as Adrian had mentioned)

Yesterday, I bought a stepping ring so I could attach my 58mm filter onto my 50mm f/1.8.
This morning at uni I put on the filter, turned the ISO up, and took some handheld shots, no hotspot!
Then just then, when I went to have lunch at Matilda bay, I took more more pictures, using longer exposures; I'm excited Too bad I didn't bring card reader or cable with me to uni, otherwise I'd load them online now!!

Excited!!
I'll post pictures when I get home.

[loopy]

Hi Adam,

What camera are you talking about? One of the things I learnt with Astrophotography was that the guys at Nikon did a hell of a job with their IR filter. It's top notch, but the problem with that is that most of the pretty red stuff you see in space comes from the IR band. For this reason, something like a D70 will turn out a much poorer shot involving IR than say a 300D. It is possible to remove the IR filter from the D70, and if anyone wants, I'll go through my links and try to find the page describing how, but I wouldn't recommend it unless it was a dedicated IR camera. It's also one of the things that stopped me from getting a decent scope for astro - and I'm not about to lower myself to buying a Canon....

Cheers,


Brad

[adam]

I'm using the 300D. from pictures I've seen, I thought the D70 was more sensitive to infrared than the 300D.
I think the link was posted on this forums last time, for some modifications; I'm at the moment, not only too scared to do it, but don't think I can do such a thing until I have another camera

Lower yourself to buying a Canon?! :|

haha

[Kombisaurus]

That's great Adam

I just ordered the 50mm f/1.8 last week, so I'm glad to hear it doesn't exhibit the hot spot of the 18-55 kit lens.
I did a couple of IR shots through my 70-200 f/4L for the first time on Sat at Kings park, and I suspect the lens actually has an IR-cut filter coating on one of its elements, as the resulting photos took more exposure than I was expecting and had much less of the "infra-red effect" (ie white foliage, black water) than shots I've taken with the kit lens. Below is a photo I got from this lens, which looks to me like it is made up of the small amount of visible light that the R72 filter lets through. It also seems to exhibit a hot-spot.



I agree with you about the 300D vs D70 Adam. From everything I've seen, the D70 is a lot more sensitive to IR than the 300D (I've seen some beautiful IR shots from the D70). Unfortunately for me when I want to take IR-shots it seems the 350D is about the same as the 300D.

There are loads of tutorials around for modding your camera and replacing the IR-cut filter ("Hot filter") with plain glass, but it seems fairly tricky for the 300D.

I think I will do that with my Olympus though, so I will have a "true" IR camera. I can always buy a Hot Filter thats screws on like a normal filter to take normal shots again, and for the Olympus at least the conversion process is reversible and not as difficult as the 300D.

But the "ultimate" is the 20Da... which is only available in Japan at the moment. It is a special version of the 20D which doesn't have an IR-cut filter, and also has the ability to use the LCD screen pre-shooting to compose and focus for small periods of time (like a P&S camera, but it can only be used for short periods). It is aimed as astrophotography.

[adam]

I'm going to go home now, I'll load the pictures when I get back.
I'm just too tired and lazy to stay around in the library any longer

and also this thought in me to find out what my aunty brought back for me, and to see how the pics came out!!!

[shuttertalk]

But the "ultimate" is the 20Da... which is only available in Japan at the moment. It is a special version of the 20D which doesn't have an IR-cut filter, and also has the ability to use the LCD screen pre-shooting to compose and focus for small periods of time (like a P&S camera, but it can only be used for short periods). It is aimed as astrophotography.

You mean this?

[adam]

im home! im home! oh so exciting! new toys to play with! and IR pictures to load at the same time~! and mum calling me to eat my dinner!! ahhhhhhh!!!
I'll be back soon!

[Kombisaurus]

hahahaha.. have fun Adam!

and yeah ST, I did mean that!

[adam]

I'm starting to think that there IS a hotspot, just spread out over the whole picture HAhaha
See if you can see it.
This picture is one of the only good ones - a 30 second exposure without a tripod - it was lying on my camera bag

[Kombisaurus]

Hey that looks great Adam. Lovely clouds.

There does look to be a faint hotspot, but it is so spread out that its not really noticable. I'm sure if you tweaked the white balance and saturation you could make it disappear, as it looks like it saturates the centre of the image slightly rather than lightening it (which the kit lens does).

Certainly it seems to respond much better than my 70-200 did to IR, and also looks better than the kit lens (see below).

Here's an IR shot I took with the kit lens the day after I got the camera. It came out OK, but check out the masses of lens flare. I think I took this exact same photo without the R72 filter, and none of that flare was visible. The sun was a fair way above the edge of the lens (but I wasn't using a hood).
It still doesn't have a very pronounced IR effect to it though, but its better than nothing (the contrast in the sky is nice, and the trees are a bit lighter). :o/

[shuttertalk]

Nice pics guys!

[Peted]

Mmmmmmm, interesting! My V1 does IR, must have a play.

[EnglishBob]

Cool pictures, but it looks to me that the filter is still letting some visible light through, the 72 isn't quite dark enough. And what you are calling a hot spot looks to me more like the filter is possibly darker in the center. True IR pictures have all the green vegetable matter a bright white color.

[loopy]

Hey guys,

Interesting you both agree the Nikons take a more sensitive IR shot - maybe it works differently with a filter attatched? I used to hook up my D70 to a mates scope, and we hooked up his 300D as well. Using the same exposure times, with the same ISO settings, etc etc, his camera caught waaaaaaaay more IR than mine did, to the point that mine was more or less useless with the in-built IR filter still in place. Maybe though the filters convert the IR light to something else before it hits the sensor? Interseting observations.

Cheers,


Brad

[shuttertalk]

Hm... I wonder whehter it could be the characteristics of the sensor too? Don't forget, Canon DSLRs use CMOS sensors, while others use CCDs.

[loopy]

Good point Jules, but I'm not sure - I know at the time I had a look around a few astrophotography forums (if you want to be blown away with awesome pictures, check out one called "Cloudy Nights", there's some incredible photographers there) and it seemed to be a common problem. All the top guys were using Canon DSLR's because of the high IR sensitivity, and those that *were* using the D70's had pretty much all modified them. I wasn't about to shell out another $2k so I could use my camera in both scenarios, and that's why I kinda moved away from that scene. That's not to say you can't produce good astro shots with a D70, it's just you'll get a better response from a Canon.

On the CCD vs CMOS, the top level guys are using dedicated and cooled CCD systems, with no filters (at the camera end). These buggers are EXPENSIVE with a capital E... it's not unusual to pay in excess of $10k US for like a 3MP sensor. They're usually monochrome too - the colour pictures are shot using compositions of filtered shots. Filters are pricy as well - rather than using the standard Red, Green, Blue filters and combining multiple exposures, they use specific wavelength filters based on the elemental composition of the object they're trying to photograph. A common one is Hydrogen-Alpha which is the light emitted when a certain isotope of Hydrogen is heated up. It gives awesome reds in the image, but I *think* that it crosses a bit into the IR spectrum, so wont work as well with a D70. Green is usually a Sulfur-III filter and blue is Oxygen-III. You're looking at a few hundred bucks though for a decent filter, so the whole setup is just a tad pricy

Sorry to get a bit off topic - astrophotgraphy is amazing and I've got maximum respect for the guys that do it. Just wish it was a little cheaper...

Cheers,


Brad

[Kombisaurus]

That's very interesting about the D70 vs 300D (and 350D) IR response. I don't doubt what you read, but I'm sure I read other people reporting the opposite. And many of the images I've seen seem to have a stronger IR visual effect from the D70 (although this might be due to a different response of the sensor as ST points out, not necessarily a higher sensitivity to IR light).

Well... I guess next time a bunch of us get together, we'll just have to do some tests. Take identical shots on each camera with identical settings and filters - see which responds better.

That's also interesting (and a little scary) about the astrophotography stuff. It fascinates me too, but these guys just take things to a waaaay new level. I have a lot of respect for their perserverence and the pursuit of excellence, but I get the feeling a lot of them must really have no life!

...not that I can talk about having a life! :/

[Toad]

I have seen some stunning infrared pictures from unmodified D70's with R72 filter - the color, depth, and tones are awesome.

However, I am not sure that has anything to do with the degree of sensitivity to IR. I also know that those shots are typically very long exposures - 10 to 30 seconds as a rule. A greater sensitivity might reduce that time significantly. Not sure that the long exposures are a real issue, however. Because infrared filters are opague - I think you pretty much have to use a tripod anyway - set up the shot as you like it - and then put the filter on...

[loopy]

Yeah, that's pretty much what I was thinking, we might be talking about different things here. A "normal" exposure for photographing a Deep Space Object is of the order of 5 minutes, and I'm doubting your IR shorts need anywhere near that exposure...

Cheers,


Brad

[Toad]

My totally uneducated guess would be that length of exposure varies inversely with IR sensitivity.

As sensitivity becomes greater - required length of exposure becomes shorter. Maybe "all" cameras can do IR if you leave the exposure long enough... (but what do I know?)

[EnglishBob]

Here's a couple of pictures taken with my Fuji 3800 before I sold it, using a hoya R72.



This was a 3 second exposure. Red tint removed in post.

[shuttertalk]

Wow, awesome! The photo just comes alive with the IR!

Hey did you have to mod your Fuji, Craig? If (err when) I get a new camera, I might convert my Fuji to an IR one

[loopy]

Toad - totally agree with you.

Also should add, apologies for being rude, these are some great IR shots. Adam mate, I think yours is my favourite, that boat looks cool

Cheers,


Brad

[EnglishBob]

Didn't mod it, that was 3 seconds with a monopod. though the 3800 can be used for handheld if you remove the internal IR filter.

[adam]

Yes, I think that true infra red in black and white, because it's not in our visible spectrum therefore it shouldn't have any colour!
Initially, the picture I took had a red tint, but I did a custom white balance;