From some posts, i read that a D70i (IR Version of a D70) is not similar to a normal D70?
so what are the differences?

Someone care to go thru it throughly?

Ok, simply put, the main differences between a normal D70 and a D70i (Infrared D70), is that the D70i has had its internal Infrared Cut (IRC) filter removed (and in some cases replaced), so as to improve the CCD’s recording of NIR.

In its original form, the D70 is quite capable of capturing NIR, using slow shutter speeds. Whilst this is fine for most landscape/abstract/architectural/still-life shots, it is unsuitable for photography of moving subjects or scenes requiring fast shutter speeds such as portraiture/wedding/wildlife/nature macro/candid etc, etc. Enter the IR Enhanced D70 (IReD70) and the Pure IR D70 (IRpD70).

IR Enhanced D70
The IReD70 is simply a D70 that has had its IRC filter removed. Excessive IR entering the CCD will blow the red channel, resulting in overly saturated reds and blues looking like purple, hence the need for the internal IRC. Note that removing the IRC filter also removes the anti-aliasing filter, responsible for reducing moiré, as the filters are stacked together as a single piece of glass. Once the filter stack is removed the camera’s sensitivity to IR increases tremendously as IR is no longer being filtered out (cut).

The filter stack is either replaced with a piece of clear glass filter or totally left off. Either way, you will need to mount an infrared pass (IRP) filter on your lens in order to take IR photos. Additionally, although this camera is capable of taking regular visible light shots, you will need to mount an IRC filter on your lens, such as the Tiffen Hot Mirror fitler or the B+W 486 filter, in order to cut out excessive IR.

The advantage of such a camera is that you will be able to take IR, UV and visible light photos and use different types of IRP filters with ease. The big disadvantage is that you will be required to mount different types of filters on your lenses for different types of photography, which can amount to quite a few filters and be quite costly. The second disadvantage, from an IR point of view, is that you will need to remove and re-mount your filters every time you compose and take your shots, so although you get faster shutter speeds, you would still not be able to effectively capture shots of non-static subjects.


Pure IR D70
The IRpD70 is a D70 that has had its internal IRC filter removed and replaced with an IRP filter of some type. Depending on the type of IR photos the photographer wishes to take, this filter could be a Hoya RM72, RM90, a B+W 092, 093, an Edmund Long Pass (ELP) filter, a Cokin 007 (P,Z,X) or any other IRP filter.

The IRpD70 is similar to the IReD70 in that they are both very sensitive to NIR, but here is where the similarities end. Whereas the IreD70 can be used for visible light photography, the IRpD70 cannot, as all light, usually below 650nm, are blocked.

What then is the advantage of the IRpD70? The main advantage is that it allows you to take ALL TYPES of IR photographs, landscape/portraiture/candid etc, etc, without the need for tripods and the mounting/dismounting of filters for shooting and composing.

The biggest disadvantage, of course, is that you will be restricted to only IR photography on this camera. The second is that you will not be able to use different types of IR filters, as the changing of the internal filter isn’t a quick affair.


Common Issues
One common issue that both the IReD70 and the IRpD70 face is the changing of the focal path to the CCD as a result of the removal of the original filter stack. Unless you can find a replacement filter that is of the same optical (not physical) thickness as the removed filter stack, you are likely to find that you would need focus compensation for all your shots. Of course all IR photography require some amount of focus compensation, but you are likely to find that once the filter is removed (and not replaced with an appropriate one) that you will be compensating more than usual.

Some have argued that not replacing the filter is actually good for IR photography as IR light focuses closer but I have not verified this.

Hope this answers the question.

Cheers,
Matt

I should have emphasised that the MOST IMPORTANT DIFFERENCEis the FOCUSING

With a normal D70 and using an IRP filter, you can sometimes get away without focus compensation. With the D70i, compensation becomes a must, unless some modification is made to the camera's focusing. Some modders have had good results with this and I will be trying it out too.

Matt,

Thanks for your in depth explanation.

One question. With your modified Pure IR D70, how would you know how much focus compensation is required and should you compensate further or nearer the main subject?

Hi deadpixel,

Thank you so much for your in depth explanation.

Extremely well put and very clear.



Cheers,
Pablo.

Teerex,

The first dozen or so shots were by trial and error. I would take a shot, compensate, take another and then several more, each time checking to see how much compensation was made. It is easier to do this with prime lenses as they all require a fixed amount of compensation whereas zooms need varied compensations depending on the focal length.

Once you get used to the amount of compensation each lens needs, I'm referring to primes here, it becomes easy to focus and compensate within a second by feel. You won't need to look at the lens.

Regarding compensation, you will always need to shorten the distance mark on the lens, that is, if it says 11m on the lens barrel, you'd need to shorten this to say 10m, for example. On most Nikkor lenses, this will result in your turning the focus ring a little to the left and on most Sigma lenses, to the right.

This may sound complicated but with a couple minutes of practice, it becomes quite intuitive.

I'll process some of these test shots over the weekend and post them here so that comparisons can be made between uncompensated and compensated shots. Also, I've modified an Omnibounce so that when it is mounted on an SB800, it completely blocks out the visible light output of the flash, effectively creating an IR "flash." I can use this in total darkness with the D70i and capture bright-as-day photos. Of course you could take bright shots without the modified IR flash-head filter but then your subject would see the flash and come after you Let me do some more test shots with it and I'll post some of the results up for you guys to see.

Cheers,
Matt

This post has been edited by deadpixel on Aug 26 2005, 10:17 PM

Thanks Matt for the explanation on focus compensation. Understand what you're saying.

So you managed to find some material that is IRP and put over the omnibounce to mod your flash into a IR flash. Is it resin material? I have been trying to look for IRP resin/plastic material to experiment as a replacement for the R72 or the P007.

Teerex,

I used two sheets of developed, unexposed, slides. Basically, I just cut out the front of the Omnibounce then completely wrapped it with two layers of the slide film.

I also just got two pieces of 4 x 4 ELPs from Edmund Optics (resin type filters) and will be cutting them into pieces and assembling the pieces into a tougher IR flash-head filter. The modified Omnibounce was good but I'm hoping the ELP ones will be better.

Cheers,
Matt

Time for me to look for a couple of developed unexposed slides liao.

Thanks for sharing your expertise Matt.

Hi Matt,
thanks for the crystal clear explanation
Very informative, thus have pinned this as a sticky thread.

Nisa, perhaps you could change the thread title to something like "Difference between D70, IReD70 and IRpD70"?

Thanks

Hi deadpixel,

You are difinately a dedicated IR photographer !!

This I am happy to see as I am shure others are also.

I look forward to your sharing of information and your IR photot's.

Thanks again deadpixel ... (I don't know exactly when I will be back to Singapore, but I do look forward to meeting you when I can !)

Cheers