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HiTech Prostop ND Filter04/08/2011 - 8:46 AM
In my last blog I was bemoaning the horrendous lead times with the LEE "Big Stopper" (estimated to be 10 months from when I placed an order in April). I ordered a replacement after my last one hit the rocks. For those unfamiliar with the term - it's what LEE called their extreme 10 stop ND filter. As a result, despite some misgivings I ordered the "new Improved" HiTech Prostop ND Filter.
LEE were by no means the first to offer a 10 stop filter - there are several available, but most are of a screw on type. These have a few inherent problems - they are prone to severe vignetting when used in conjunction with standard slot ND graduated filters, the positioning of which is almost impossible - as when a "Big Stopper" is in place the viewfinder is completely obliterated.
I had read both on ePhotozine and elsewhere on the net, HiTech's previous "Big Stopper" offerings, have suffered from a quite ugly magenta/brown colour caste, caused by its inability to stop IR light in the same proportion as visible light. I have also seen this in Hitech's standard range of filters, when stacking say a 3 stop and a 2 stop ND grad - it was the reason I replaced my HiTech's with the LEE system some time ago. Many will say "Yes but that can, be corrected in Photoshop / Lightroom" well no, with it been IR radiation that's recorded it alters the luminosity and reflectance from different, for example water absorbs IR almost completely, whereas green foliage reflects it.
Lead times - From ordering to receiving the product it was 5 days, a vast improvement on LEE's 10 months.
Packaging - It came in a plastic leatherette pouch - very professional, a big improvement on the plastic sleeves that their grads come in, although it must be said not quite as impressive as LEE's pouches.
Pricing £72 (inc VAT) so about 25% cheaper than LEE.
I took the filter out last night to a spot local to me. Not ideal the light disappeared, the nice fast moving cumulous clouds been replaced by a thundery cloud layer. However it was these conditions, I was often unhappy with HiTech's ND grads, so not complete right-off.
I tried a couple of compositions (only one shown here) - all with a Nikon D700, with a Nikkor 20mm F2.8 prime lens.
My first impressions of the filter in place were good, the light seal seemed if anything slightly better than LEE's big stopper. The biggest difference from the LEE big stopper is that HiTech use a CR39 optical grade polymer (as opposed to LEE's glass filter), so I would expect it to be a little more forgiving than LEE in terms of knocks and drops, but may scratch more easily.
The following images are straight Out of camera, no processing at all (it took me a while to figure out how to set RAW+JPEG as I always work in RAW).
You will notice, rather than a magenta caste there's more of an turquoise colour, to the big stopper image.
On the RAW file I then took a white balance measurement off the gate (using the same point for both images). Then equalised the exposure using auto (in lightroom)
As you can see the WB can be corrected quite easily, I didn't alter any other setting, I could have optimised colours more using the HSL sliders, but I actually prefer the slight warmer tone to the darker shades with the Big stopper.
I found my version to be nearer 11 stops than 10. A 1/13th Sec standard exposure, gave rise to a 166 second exposure with the Big stopper in place (I chimped to optimise the histogram). I was concerned about the heavy filtration on a plastic filter would significantly affect the clarity and resolution of detail - I didn't see any deterioration in this respect. One point I will keep an eye on, there were a few white flecks in the sky, it didn't look like dust bunnies or long exposure noise - it will be something I will be looking at closely.
Whilst not been ideal conditions I did manage the following image from the RAW file.
I make no apology for converting it to B&W, that is the main reason for buying a Big Stopper. OK far from ideal, not good enough for my PF but I'm reasonably happy with it.
In the forums a while back, I stated the viewfinder had to be covered or you get severe light leak problems. This is what you get if you don't use the D700's inbuilt viewfinder shield.
I leave it upto you to draw your own conclusions !
I was relatively impressed with the findings, so will give it a guarded thumbs up based on these results. I'm looking forward to using it in good light conditions, where I can give it a good thorough test.
Would I recommend it? It's a bit early to say, but as you will have to wait until 2012 to get your hands on the LEE version it's probably your only option for a slot type. I must say I was mightily impressed with HiTech's customer service and turn around time.
I look forward to hearing your findings.