My Work

Well, this is not really a blog but a place for me to place some links relating to my work as an EH&S professional.

China MOH GB page

Quick Test Nikon AF Nikkor 80-200mm f/2.8D (2 Touch)

Decided to do a quick "window" test of my recently acquired (used) Nikon AF Nikkor 80-200mm f/2.8D. My second so called "pro" zoom lens, the other being the Nikon AF Nikkor 20-35mm f/2.8D.

Test totally unscientific, hand held. Nikon D300 in Aperture Priority, ISO200, Picture Control D2x Mode 1, 12-bit raw, batched converted and resized to 1024 width using Photoshop Elements 6.0.

Oh the comments are based on overall impression, not pixel peeping; i.e. looking at the photos in quick succession rather than examining the micro details.

10 April 2010 - did some field test with this lens. See AF 80-200mm f/2.8D Revisited.

Performance Wide Open and 1 Stop Down

First the extremes: 80mm and 200mm, at f/2.8 to f/4

Click on photo for 1024 width photo.

80mm f2.8

80mm f/4

At 80mm, there did not appear to have much improvement in resolution/ sharpness/ contrast going from f/2.8 to f/4. More actual photo tests would be needed to confirm this.

200mm f/2.8

200mm f/4

200mm f/5.6

At 200mm, the improvement in resolution/ sharpness/ contrast going from f/2.8 to f/4 was significant! Less so with 105mm and 135mm but still visible (you'll have to take my word for it). It begs the question if I should avoid using 200mm f/2.8... Will need to test this out in actual photo situation.

Performance at f/5.6

Next I figure that most time (other than those low light situations) the lens would be most used at f/5.6. So a series of photos at f/5.6 were taken for the marked focal lengths.

80mm f/5.6

Hmmm, nice and sharp.

105mm f/5.6

135mm f/5.6

200mm f/5.6

Yes yes yes...

So the lens is really nice and sharp throughout its range at the most frequently used apertures of f/4-f/8 (take my word for it, or you do your own tests). At f/2.8, there is some softness noticeable at all focal lengths except 80mm, so more test are required to see if I can live with the softness wide open.

Conclusions

With this limited, unscientific, hand-held test, the lens came off with almost flying colours. I will need to see if 200mm at f/2.8 is so weak that I cannot use it... Hopefully not.

Epilogue

I had always wanted to see what the diffraction effect was but had never tested it. In field situations when shooting macro both UW and topside I had used f/16 and f/22 quite generously, and had not seen any visible drop in sharpness. Well, I had nothing to compare with.

So I did a short test and gone all the way to f/16 on several focal lengths.

200mm f/11

200mm f/16

My my, the difference is evident! There is indeed lost of sharpness at f/16.... Well not that I am likely to use f/16 on a tele-zoom...

Similar results are seen in the other focal lengths.

Strobe Colour Temperature and Blue

Saw Alex Mustard's article "Strobes and Water Colour" after I asked the question "Warming Filter On Strobe, What does this do to the blues?" in the wetpixel forum.

Quote Alex Mustard:
"The root of this phenomenon is that the various underwater strobes on sale produce light at different colour temperatures and digital cameras have adjustable white balance that reacts to this.

When you take a picture illuminated by 5500 K or 4300 K light you will need a white balance close to this value to render neutral colours. This setting is applied to the whole image. In the real world this means that both strobe lit and non-strobe lit areas are affected, and therefore strobe choice can affect the background water colour."

So off I went to re-process some of my raw photos to see the effects for myself. I used twin Ikelite Substrobe DS125 and DS160, both balanced for 4800K (didn't know this until I started considering Alex's article). Camera used was Fujifilm S2Pro, lens Tokina AT-X 107 AF DX Fisheye AF 10-17mm f/3.5-4.5. Camera settings: ISO100, Manual Exposure 1/60s f/8, lens at 11mm, Strobe set on TTL.

See conversions of raw photos at different colour temperature below:



Interesting although subtle shift in the background blue. Which is better?

My take right now is the one given a white balance of 4800K is the "correct" foreground colour, while the blue in the background is probably that tiny bit more saturated than the actual scene. But then again the blue is the background is a function of what combination of shutter speed and aperture I use, so the "actual" blue is again never quite well defined.

I'd go for the 4800K shot.