My first 5x4 Negative . Making Aperture Scales?

I just produced my first successful 5x4 negative and as this is such moment I

thought I would share it.<br>

I used Fomapan 100 developed for six and a half minutes in Ilfosol at 19 degrees

C in a Paterson 10x8 Thermodrum with constant agitation. The lens was a 210mm

f5.6 Industar 51 barrel lens mounted on a home made lens panel on a Crown

Graphic. Exposure was 8 seconds at f22 and was made against the light. An

incident reading was used to establish exposure and and extra stop given to

allow for bellows extension<br>

The result can be seen <a href="http://photobucket.com" target="_blank"><img

src="http://i176.photobucket.com/albums/w170/crown-graphic/5x4%20IMAGES/Test54jupiter51.jpg"

border="0" alt="Photo Sharing and Video Hosting at Photobucket">here</a> <br>

 

Because my scanner (Epson 3590 Photo) will not do a 5x4 negative scan I have had

to scan the neg as I would a print but used a 600dpi setting rather than a

300dpi setting. I then inverted the result in Photoshop.<br>

Does anyone know a better workaround than this? Other than buying a new scanner

of course. <br>

On another note I have just acquired a 240mm G Claron which I have mounted in

Copal Press No1 shutter that I picked up for dead cheap.I do need to make an

appropriate aperture scale though. Does anyone have any suggestions for

materials and or methods to do so. I think I am Ok with the maths having looked

at previous posts on this topic. ie focal length divided by aperture diameter

equals f stop seems to be a good working calculation. I have a set of callipers

and (careful) access to the diaphragm for measurement purposes. It is the

material and engraving technique I am at rather a loss on at present.

Steve

Even with a transparancy adapter, I have never been happy scanning B&W negatives on my flat bad. Just make contact prints and scan them. There used to be some very cheap contact printers for 4x5 that had a bulb and frosted glass.

I needed to make an aperture scale, so I drew it up in PowerPoint and laser printed it on paper. Then I stuck the scale (after cutting it out) on double-sided tape and stuck it to the lens.

 

Vick

You can do really cheap contact-prints with a 10x8 frame from Art shop comprising nothing but glass, thick cardboard backing and clips, and either:

a) printing-out paper (POP), a moderately sunny day, and some hypo to clear it, or

b) proper photo-paper, a small low-power flash gun (one ceiling-bounce flash required, filtering possible), some maco ecoprint developer, trays and fixer

 

I did both of these last year before finally getting an epson V700.

 

Holding POP tightly for 10mins to keep the registration between neg & paper gets uncomfortable.<div></div>

I made a scale in Photoshop and printed it on self-stick label paper.

 

Also, Schneider sells a two-scale set (top and bottom of shutter) about $80 US. phone

818-766-3715, PDT.

Just remember that you calculate the f-stop from the diameter of the entrance pupil not the diameter of the iris itself. The entrance pupil is the image of the iris that you see when you look into the front of the lens. If there are no lens elements in front of the iris, then the entrance pupil diameter is also the iris diameter, of course.

 

Best, Helen

I think I may be able to make a a scale via the Photoshop method; sandwich it between two clear pieces of plasic (or laminate it),then screw it into the area occupied by the existing blank metal F stop scale<br>

Thanks for your explanation of the entrance pupil Helen; I would indeed have used the bare iris measurements. I suppose once the first 3 F stop positions on the scale have been calculated I can deduce the positions of the remainder. The thought also just struck me that I may be able to make a digital copy of the existing stick on scale, edit the F stop values in Photoshop and reprint it life size.Lots for me to ponder here.I shall not be rushing out to buy a set of scales from Schneider though; not for well over what I paid for the whole shutter.<br> I had considered the POP printing solution and am quite keen to give this go but Retrophotographic were out of POP paper last time I looked . The idea of adapting a 10 x 8 clip frame to create a contact printer appeals strongly to my DIY instincts!<br>

Thanks everyone for your thoughts.

Cheers, Steve

In addition to what Helen Bach wrote: <p>The difference between entrance pupil and iris diameter is the factor by which you can divide the focal length in order to get the basis for determining where the stops should be. If for example max. e.p. is 36mm while the iris diameter is actually only 30mm (factor 1.2), you may use a focal length of 175mm (210 : 1.2) for stop calculations. F8 in this case would correspond to closing the iris to 175:8 = 21,9 mm. <p> Uli

Thanks for that last post Uli.It is easier for me to measure the actual iris opening than the exit pupil, so if I understand you correctly this should also be true:<br>

The Lens is rated 240mm f9. The actual maximum iris is 30mm so the notional focal length for calculating true f stop values must be 270mm, ie 9 x 30mm = 270mm.<br>

By measuring the actual iris opening with the front element off I can calculate f stop positions on the shutter housing. ie when iris diameter is 6mm then effective aperture is f45 (270/6) once the front element(s) is replaced.<br>

I have yet to produce an adequate scale but I will get there eventually I am sure.<br>

Thanks Steve