Category Archives: Photography

Frustrating couple of days – light leaks

Saturday – A trip to Lacock Abbey and the Fox Talbot museum with the 10×8 and 4 negatives to shoot – sadly 3 big shadows on the images.Lacock-Nov2019-2

I ran a test on another fresh negative at home on Sunday morning and then went to Clevedon Pier as the day was grey and overcast – low contrast lighting which I was waiting for and 3 out of four shots here too with dark shadows.Pier-lightleak-2

I put a battery LED lamp inside the camera in the darkroom and went through the motions of adding the slide carrier, exposing the negative and replacing the dark slide  to see if any light leaked out. On the second attempt yes – a light leak from the top of the camera as I was moving the dark slide. This was because one of the flimsy catches holding the camera back in place had slipped undone – something I noticed had happened at the pier, so I am pretty sure that is the source of the leak. I have added a strip of black felt along the top of the back of the camera body to help make a tighter seal and hopefully make the catches engaged more firmly. – So we try again tomorrow.

Here is the one more successful image of Lacock and Fox Talbot’s window.Lacock.jpg

DIY large format enlarger

Successful experiment to to use 100 yr old field camera as the enlarger for the 5×7 negatives taken with it. Key breakthrough was using a kindle then an ipad as the uniform light source. Now I can make 10×8 prints instead of just contact prints from these negatives (x-ray film). Initial horizontal test to establish distance needed (40cm) then tripod mounted. Just the light leaks to seal and we are good to go.

Some Success with Waterfalls

Today I took the 100 year old large format (10×8) camera to Wales – waterfall country. Recent heavy rains meant a good flow of water over the falls.

I took 4 pieces of pre-flashed photo paper in the two dark slides plus some spare paper and my black-out changing bag. Today I would see if it was feasible to change the sheets “in the field”, having practiced at home in the darkroom – it did work , so I’ll definitely use the method again.

reasonably successful images of the first set of falls – I was exposing for mid grey – but the brightness of the water is blown out – so next time I’ll try underexposing and then leave the paper in the developer longer to bring out detail in the shadows – I think that’s how it works!? Exposure times of 4 -13s at F11-22 ISO 6.

The second waterfall site I visited – Henrhyd Falls was much more challenging as there was a lot of spray being blown off the falls. Also the tripod head wasn’t stable and kept moving so only one picture here. (4 seconds at F16 ISO 6)

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All images here are scans of the original paper negatives which have been made positive in Lightroom.

welsh waterfalls_Fuji-XH1-digital

Still life successes

Using my antique (1900s) large format (10×8) bellows field camera I have been making some successful still life images.

I decided to move away from the uncontrolled variable light of the kitchen window to the fixed lights in my studio (dining room). This removed one variable from the exposure equation allowing me to make reliable test exposures on strips of the photo paper negative I am using. This saves the expense of wasting large sheets of photo paper on improperly exposed shots.

Whilst I am pretty happy that I can measure the light needed with my iphone app based on iso 6 for the paper negative, there are three other variables that come in to play.

1. At larger f stop values (smaller holes in the diaphragm) a small variance in position of the lever or ring setting the aperture has a disproportionately greater effect on the actual aperture used – at f64 on one lens a small tweak can make it effectively nearer f128 – doubling the required exposure time!

2. The bellows effect. Stretching the bellows past the focus length of the lens for close objects decreases the light intensity falling on the negative by an inverse square proportion. Doubling the distance decreases light intensity to a quarter. So 4x the exposure time is needed.

3. At longer exposure times, the longer the exposure the longer you need to achieve a set increase in darkening of the negative. So for a 2 minute calculated exposure I would expose for 2.3 minutes.

With these variables in play it pays to take a test exposure on strip of photo paper before committing to exposing a whole sheet.

For many of the still life images I am using a shorter (8″) focus length lens as this gives the greatest magnification. However it only stops down to f22,rather than the f64 of my other lenses, thus limiting the depth of field achievable. Accepting this limitation I have chosen subjects which do not demand a great depth of field – and am very pleased with the results.

I also added a graduated neutral density filter for the fennel photo to darken the bright base to get a more evenly exposed picture which seemed to work (see bottom photo).

Lens problems with The New Countess

Today was time to take the New Countess full plate camera to Clevedon and try some images of the wonderful Victorian Pier. Shame it was so breezy – not ideal for longish exposures with a huge camera like this one!

With two slides I had 4 exposures to make. It was a good opportunity to try the (supposedly) F384 lens too as it was a good focus length (12 inches – 300mm ) for the job.IMG_2026

Bringing the exposed paper negatives home for developing, I found that the lens I was using – Rapid Aplanat No.3 Ser.D.F.8 (R.O.J.A. vorm. Emil Busch, Rathenow) – was not operating at the indicated F stops – see the title image!

I had tested it in the garden on the pear tree using the widest aperture with no problem – but at the indicated f90 it way over-exposed the image (Paper negative). I tried a couple of other lenses at the same time successfully so thought I’d make some measurements of the diaphragm aperture with digital callipers and calculate the theoretical f-stop  (dividing the focal length by the aperture diameter)

As the F stop numbers increase the variance between the indicated F stop and the calculated one increases greatly. Column headings are Focul length, Diameter (of aperture) in 100ths of an inch, The F stop indicated and the F stop calculated.

Screenshot 2019-10-09 at 16.16.14

Using a more familiar lens at F45 for a 2 second exposure I achieved a reasonable if (wind) shaken exposure.

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Large Format Portrait – Artificial Light

With its custom replacement glass screen fitted (https://www.ebay.com/usr/virgisst ) I have made some further tests of the recently acquired full plate (10×8 inch) camera (The New Countess). I wanted to test how well the camera could be used with artificial lights since the paper negative responds differently to film.

NewCountessCamera-12NewCountessCamera-9

My first shot was with a short focus length f6.3 lens and an exposure time of 2 seconds. With two large fluorescent bulb lamps, this produced a well-exposed image but the depth of field was very short. To gain depth of field I changed to a lens that went to F64, with a much longer focus length.

NewCountessCamera-14

However the sliding control moves past the “64” and my first images were way under exposed as the aperture was much less than for F64.

Further test strips gave me an exposure time of 35 minutes. Below are two images; F22 on the left, F64 (+) on the right. The difference in depth of field is evident.

Clearly a 35 minute exposure isn’t appropriate for portraiture. So extra illumination is needed to keep depth of field as great as possible. There is no real substitute for daylight!

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Progress with the New Countess

A windless, bright day meant I could take the Countess into the garden and learn more about how it performs.

Successful experiments with low light and hight contrast situations have been encouraging. Focal lengths from 4 to 10 inches were tried with F stops from F6.3 to F45.

Exposure times ranged from 2 to 10 seconds.

However focussing is still difficult – I was waiting for a replacement screen that arrived a day later.
Here are pictures to show the difference in screen thickness.