Large Format Photography Australia

Noosa River, Warning Buoys, Dusk

Gelatin-silver photograph on Ilford Mg IV VC FB photographic paper, image area 24.5cm X 19.5cm, from a 8x10 Tmax 400 negative exposed in a Tachihara 810HD triple extension field view camera fitted with Fujinon-W 300mm f5.6 lens with the front lens group removed yielding an effective focal length of approximately 580mm. A #25 red filter was added to minimise residual chromatic aberration and enhance sky detail.

Nice image, Maris, and an interesting tactic to achieve a long focal length. Is that lens designed as a convertible? Anyhow, it worked well in this case.

Thanks Barry, The Fujinon-W 300mm is a conventional 6 element plasmat design and all such lenses can be un-officially converted. Precautions include:
Focus at least a couple of stops down from wide open. That takes care of most of the focus shift that happens as the iris closes.
The strong #25 red filter soaks up any uncorrected chromatic aberration.
The soft corners don't show because there's no fine detail there, only sky and water.
Careful with the vulnerable shutter blades, there's no glass in front of them.

Maris, very interesting, I didn't know you could do this. Do you know if there would be less problems at the edges of the lens if was not a W (wide) coverage lens?

Did you just hold the red filter in front of everything, or place it inside behind the rear elements?

Nice image by the way.

Mick.

Thanks Mick. The longer focal length with just the rear lens group behind the shutter also delivers a much bigger image circle. But image quality degrades quickly away from the sweet spot at the centre. The 8x10 format uses only the middle of this big image circle and tolerable image quality is available with enough stopping down. I set f64 on the lens but with the stretched out bellows the working aperture was f128!

The fujinon-W 300mm has filter threads on the rear lens group and a 67mm #25 red fitted nicely. Rear mounted filters introduce spherical aberration and a focus shift equal to one third the thickness of the filter. Focussing with the filter in place dodges these problems...somewhat.

Hmm, really interesting now.

I myself haven't noticed much, if any, image degradation in the past when placing colour correction gels behind the rear element using Blu-Tack that is.

But, we were more interested in getting transparencies to dead correct colour for four colour printing. Exposure and possible image degradation, would have just been adjusted out a bit further down the track, as by the mid eighties, all trannies were used for colour stats for pagination to get page by page approval from the art director (sigh), then they were drum scanned for electronic pagination.

Although I wonder about image degradation happening enough with the lens being used in its complete form, as opposed to the front half of elements missing.

This has given me an idea for portraiture with my Fujinon f/5.6 250mm W (wide) lens on 4x5".

Bellows length could be an issue with my Shen Hao, but shouldn't be a problem with the Toyo 45G monorail.

I feel a bit of fun experimentation coming up.

Mick.