IR72 Filter exposure issues

Along with my cheap ND400 I bought a cheap IR72 filter, again just to play with the effect more so than anything else. Again the filter is for my DA 18-55 AL II lens which I would like to replace in the future.

As some people may know, DSLRs have a filter in front of the sensor which blocks most of the IR wavelengths of light at upto 95% effectiveness. This means that when you go and place a filter in front which blocks all visible light below 720nm (like an IR72 filter) your required shutter speeds get VERY long.

Upon receiving my filter I went about taking some shots at ISO1600, 0.5sec, f4.5 handheld (got to love that Pentax Shake Reduction). What I found was that the images just came out like I had a red filter in front, not very IR at all. Today I finally got my tripod out and did some testing, I found to get a proper IR like image I needed to shoot at around ISO400, 30sec, f11 in broad daylight. The effect that you want from an IR filter is tree leaves and grass coming out white, while everything else is more like a black and white image (probably with a very red cast to it from the camera though!)

So here are some key points for shooting IR with a modern DSLR which has the sensor IR block filter still in place.

  1. Shoot RAW – you will need to play with the white balance quite a lot to get a decent image. RAW also allows some give in exposure which means you dont have to get it exact (I am finding it hard to find the sweet spot).
  2. Shoot in Manual mode – you will need to play with aperture, ISO and shutter speed to get a good exposure. The camera won’t really know whats going on.
  3. Go for LONG exposures – If the shots are not coming out how you expect (looking for grass and trees to have white leaves) don’t be afraid to up the exposure some more, and then some more again! Remember I needed to go to 30 secs at ISO 400 to get the proper effect with my camera. Different cameras will have different filters on the sensors though, so play with your camera to find out what works for you.
  4. Check your focus – AF should still work fine, however, it may shift slightly from what is the correct focus distance (due to light wavelengths). So make sure you check that the things you want in focus are actually in focus.

Cheap ND400 filters

I recently bought a cheap (very cheap) ND400 filter on Ebay for my DA 18-55 AL II lens. I picked the cheap option because I just wanted to play with the effect, but didnt want to spend lots on a filter for a lens I hope to replace soon.

Anyway, back to the point. Colour cast. This is where the quality difference really becomes apparent. The cheap filter produces a very pronounced purple cast. I havent tried to process any of the images yet, it is possible that setting the white balance can overcome the colour cast, but it should not be necessary.

Just another case of getting what you paid for I suppose! I will post some samples of pre and post processing soon.

UPDATE: Shots and details now available.

Choosing a Tripod

In choosing a tripod I had to limit myself to something around $200. In this range there are few options which are of a large size. I looked into the Velbon range, but I was a bit concerned about the build quality. Teds Camera had a special going on the Slik 500 DX Pro at the time. It’s actually huge, stable and perfect, and of course much cheaper than the similar sized Manfrotto 055 series.

When purchasing a tripod, remember its probably worth splashing out a bit, because this is something that can last forever! A good stable tripod will always be useful. The Velbon range was a bit cheaper, but not as stable. The Manfrottos were much more expensive, and smaller and lighter. The 055 is about the same in stability (in my opinion) but I found the Slik to be more stable than the popular Manfrotto 190 series when comparing in the store.

Last lens purchases

My final purchase was from a local forum which has a photography section. A member had upgraded his telephoto lens to something a bit faster and had his slower Pentax FA 100-300mm f4.7-5.8. I was looking to buy an AF telephoto lens at the time, so I checked its rating on the PentaxForums lens review section, and snapped it up.

This leaves my current line up as follows – Pentax DA 18-55mm f3.5-5.6 AL II, Pentax F 35-70mm f3.5-4.5, Pentax FA 100-300mm f4.7-5.8, Pentax M 28mm f2.8, Mir-1 37mm f2.8, Pentax M 50mm f1.7, Helios 44-2 58mm f2.0, Hanimar Auto S 135mm f2.8.

More Gear!

After buying DSLR I went a bit Ebay crazy for old P/K and M42 lenses. It turns out this is not the best idea if you dont really know what you are buying, which i did not. I ended up with a few cheap lenses, many of which had some sort of mechanical issue.

I realised I was wasting money. I did some more searching around and discovered This site provides some good insight into which lenses are worthwhile, and the trading section provides a good place to acquire all sorts of Pentax gear. The general consensus is that SMC (super multi coated) Pentax lenses are the pick for build quality, colour and contrast.

I went back to Ebay, and kept a good lookout for some decent SMC Pentax lenses. I managed to get hold of a Pentax SMC -M- 28mm f2.8 lens for a reasonable price. It is quite well used but it is lovely and sharp, and a great focal length on a digital APS-C sensor. Added to this were the two lenses I had borrowed from Dad’s old K1000 kit. A Pentax SMC -M- 50mm f2.0, and Tokina 100-300mm which has some hazing in the rear elements, and the one good lens from my previous Ebay purchases, a Hanimar 135mm f2.8 M42 which seems to be quite good.

Later I got hold of a Pentax SMC -F- 35-70mm f3.5-4.5 on Ebay for a cheap bid. This is a well regarded older Pentax AF lens, it is quite small, sharp and cheap. Then I went looking for a better 50mm. I found a Pentax SMC -M- 50mm f1.7 (the sharpest of the Pentax 50mm’s) after putting in a low bid. Soon after I was able to upgrade that to a Pentax SMC -A- 50mm f1.7 (has camera controlled aperture) for about the same price as the -M- cost me. I sold the -M- soon after.

Missing from my lens range was a telephoto lens. I bought a Tokina RMC 70-210 f3.5 manual focus lens from PentaxForums for a reasonable price. It seemed like a good cheap manual focus alternative while I waited to be able to afford something better. I took some very nice shots with this lens.

My Camera Dilemma

When I first looked at SLRs in mid 2008 I was looking at something small, the smallest one there was in fact – the Olympus E420. I played with 1 in a shop, but decided I wasn’t ready to buy yet.

After discussing DSLRs with my Nikon and Canon owning friends at length, both seemed to recommend a Canon. So I went to get a hands on look at the 450D at my local camera store. However upon closer inspection I discovered the 450D to be quite uncomfortable to hold, it was a bit too small for me to grip nicely. This threw a bit of a spanner in the works, as the 40D felt lovely and comfortable, but was outside my price range by quite a bit.

It was at this point that I remembered that my Dad used to have an SLR. I gave him a call and discovered he had a Pentax K1000 with a few lenses. So I got into looking at the Pentax DSLRs. As it turns out, Pentax DSLRs are compatible with all Pentax lenses (some via adapters though).

Once again cost came into the equation – the K20D was about the same price as the Canon 40D – out of my price range. The previous model was the K10D. This seemed to be a good option. I had recently seen a Samsung GX-10 sell 2nd hand for less than half the price of a new K20D (the Samsung GX-10 is a rebadged K10D).

I decided I was ready to purchase a Pentax K10D, 2nd hand. They were cheap and plentiful a month or 2 earlier. Demand seemed to have suddenly peaked, availability was down and prices were up. Then I discovered the Pentax K200D. Slightly smaller than the K10D/K20D/40D, but larger than the Canon 450D, and with the same sensor as the K10D. It seemed to be a competitor to the 450D but had in body IS (SR) and had a top LCD, which the 450D did not. Pricing was cheap, very cheap compared to the 450D.

I went shopping for good prices. After a couple of weeks I dropped by my local JB Hifi, the K200D was on special for only $644. About 2 hrs later I went back to the store and I was the proud owner of a Pentax K200D DSLR with a Pentax SMC DA 18-55 AL II f3.5-5.6 lens.


I have decided to start recording some of the information I collect in my brain before it comes too full. I read a lot of forums and general stuff on the internet, lately I have been particularly interested in photography. So I am going to try to pool any useful information I gather here. I will also do some equipment reviews, link to some bargains, link to other interesting blogs, articles, photographers, photos and so on.

Hopefully this blog can be useful to someone out there. I know it will help me to keep all my info together, and make it easy to find those little details I had forgotten about!

A Blog of my Photographic Journeys, Equipment, Techniques and Images.