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Wonderful imagery.Quote:
Originally Posted by arri
I measured my Verito 8 3/4" with the aperture set at f8 and the front cell off and the aperture measures 21mm, which would come in at f17.
f10 at 355.6mm (14") would be 35.56mm aperture diameter. That works out to about f4+1/2 on the dial. If I am right ( and my math skills are declining) then your comparison was f17 vs f9, which goes a way to explain the sharpness of the Verito image.
I wondered if you made the images all the same magnification "in Camera" or "in post". Would it make a difference? Or are they all just close in Focal length.
The lenses were all around 360mm (14") but little differences are possible.Quote:
Originally Posted by cowanw
The samples showing the whole negativ, no crop.
I have to set always new when I change the lens because the flange focal distance is different between the lenses. The longest register has the Imagon and the shortest the Perscheid lens.
To set the shapness the position of the camera will be changed as well. I try to set the focus only by the front but sometimes it is getting to short, than I have to change the rear too and this changes the perspective.
Quote:
Originally Posted by cowanw
Interesting, my Verito has at f/4 a diameter of 40mm but at f/8 it is 25mm
This gives an aperture for the rear cell: 14" (360mm)/1" (25mm) = f/14
I see that I have to make a table or better a second aperture scale for the rear achromat to avoit this pity.
I canŽt explain why your lens has a diameter of 21mm at f/8 and my lens has 25mm.
But IŽam sure that the Wollensak company had a reason to do like this. IŽam only a user not a lens designer.
Mine reads 25mm at f8 also, when seen through both front and rear lenses. But does one reread the diameter of the 14 " setup with the rear cell only or with both cells on? That seems to make a difference as the front cell enlarges the apparent aperture.
Oddly a 40mm f4 aperture in an 8 3/4" (355mm) lens is f5.5 according to the formula: f number=focal length/Diameter of aperture.
In any case, your Verito's f14 is a ways away from the WZ's f9. Your f4 40mm aperture would be f8.8 at 14" focal length and would be a better comparison for the WZ (f9), maybe.
All very nice rendering though, throughout.
Yes, there is a lot of things I have to think about, little mistakes given bad images.Quote:
Originally Posted by cowanw
BTW, the achromat of the Verito is a good corrected lens, it has less distorsion than the Imagon but is not as good as an achromat for a astronomical refractor.
I guess it is colour corrected as well but the menicus in the front of it destroits this. I use the complete Verito lens only with a yellow or a yellowgreen filter to avoid the focus shift.
When you look in this forum you can see samples were the focus shift were not corrected, the sharpest point of the picture wents towarts the camera.
This is a problem all soft focus lens have when the colour correction is not good enough.
Heinrich Kuehn and Dr. Staeble searching and testing a lot of different achromatic lenses to find the optimum between the best possible colour correcting and the necessary spherical abberation.
The story of the soft focus lenses is very interesting and is not finished, I think.
It's always great that new (young) people pick up the passion for this style of photography.
HereŽs another sample I made with the 250mm single meniscus lens, star shape aperture f/8
Yellowgreen filter -1
Tetenal Work enlarging paper, 18x24cm size.
Ratio 2:1
https://live.staticflickr.com/65535/...11e4e144_b.jpg
Absolutely beautiful!
Bark & Leafs
Rodenstock Imagon 210mm H/5.8 @H11 (DIY made star shape aperture)
I guess it is a prototype of the Imagon
Fuji Xray film UM-MA, sheet film 9x12cm, ISO 100, Wehner Developer
https://live.staticflickr.com/65535/...61b5a613_k.jpg