Isco-Goettingen Iscorit 5.6/75, square diaphragm

alex ph · Joined: 16 Mar 2013 Posts: 1571

Here is a German enlarger lens Isco-Goettingen Iscorit 5.6/75. That's a nice small glass put in plastic barrel and equipped with square diaphragm which is visible even at its f5.6 largest value. The lens has only three aperture positions: f5.6, f8 and f11. My copy does not have the Iscorit name on its beauty ring, just "Isco-Goettingen 5.6/75".

Photos are taken with Sony Nex, with autocontrast applied and mostly with further contrast and exposure tweaks.

#1 General rendering and colours

#2 I have not pixelized the left part of the shot! It's just bokeh at f8.

#3 The bokeh is not always like that, in some other (similar) shots it's pretty mild.

#4 Another version of the bokeh

#5 Yet another one

#6 Sharpness is very good starting at f5.6, and further. A 100% crop, unprocessed

#7 The lens is neither bad for street shooting and portraits

#8 After applying autocontrast, colours look punchy

#9 The lens renders well architecture

#10 Also in BW

#11 Another shot converted into BW

General conclusion: a suprisingly good lens, in spite of its cheap looking exterior and limited speed options.

caspert79 · Joined: 31 Oct 2010 Posts: 2926 Location: The Netherlands

Interesting. The first time I see squared bokeh Like 1 small

Slalom · Joined: 10 Dec 2017 Posts: 151 Location: Stourbridge

Square Diaphram Square effects perhaps.

alex ph · Joined: 16 Mar 2013 Posts: 1571

Thank you, caspert79! In fact, there are some better known lenses with square aperture / bokeh. Soviet Helios and Zenitars have this sometimes. There are also DIY projects and tutorials that you may find online.

I'd say it's good when you may regulate it at your taste. Otherwise it may impose too distractng or shockingly "pixelized" images, as in the shot #2 above.

alex ph · Joined: 16 Mar 2013 Posts: 1571

The lens itself. The third shot is taken side by side with its closest relative, Isco-Goettingen 5.6/50, with which it shares key parameters including the look.

#1

#2

#3