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Any hope for this lens?

Ardpatrick

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Sep 7, 2023
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Location
Ireland
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Med. Format RF
Someone gave me a 240mm G-Claron barrel lens in very poor condition.

I did a quick clean up but there is serious gunk on the front element that won’t just wipe away.

Is this a paperweight or is there any hope for cleaning this up?

As none of the shutters I have seem to fit I’m inclined to think of it as an enlarger lens. I don’t shoot 5x7 but a 240mm Rodagon I have isn’t great either!
 

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It's only covering a small portion of the front element and it's all on the edge. I bet you could be pleasantly surprised if you tried it out. Wonder how it got like that though. Kind of looks like the hardest to clean crevices of my vacuum cleaner's internals.
 
Might as well try it out, you might be surprised.

Front Element Scratches

We had a chance to make a pretty fun demonstration today, and here it is. As most of you know, we’re very finicky about our gear. We don’t like even tiny scratches on front elements or dust in a lens (although a bit of that is inevitable). We’re like you. We want the lens to [...]
www.lensrentals.com
 
Cut a half moon shaped section of lens cleaning tissue and saturate it in lens cleaner.

Paste it on the dirty section of the lens and turn the lens upside down to soak for about 10 minutes.

Try again to gently wipe off the crud. See if it will loosen with some extended damp time; bet it does.
 

major construction site. walk away unless you enjoy challenges.
 
It's just gunk on the front, which is not as bad as gunk inside. It might be cleanable or have less effect on images than it looks like.

This is the later version, Plasmat type, of the G-Claron (serial number says that). I think it should in principle fit in a Copal/Compur #1 shutter, but you can measure the lens cell thread diameters to be sure.
 
Go for it, you have nothing to lose except a half hour of your time.

If that crud is water soluble then Windex or lens cleaner may remove it.

Otherwise try denatured alcohol or acetone.

The damage done to a lens like this comes from scrubbing. Use the most powerful cleaner you can so that the gunk wipes off easily.

As usual, advice worth price charged.
 
Thanks for the advice all. As Nicholas says, I have nothing to lose. I got it for free. I'll tentatively try soaking in lens cleaner on a lens tissue, and see where it is thereafter.
 
blee1996 said:
Does look like an enlarged lens. Get it into shutter might be difficult and costly. Otherwise G-Clarons are great little lenses.
Click to expand...
Huh? According to Schneider 240/9 G-Clarons were made to fit Compur #1 shutters.
 
I have a spare Copal 1 shutter. My recollection is they are the same size as Compur 1 shutters. I will try it out.
 
If you wanted to flip it for profit, it's obviously not everyone's first choice. However if you actually wanted to make images, that loss of real estate at the front won't show up in your images. At all. Plus it will cover 8X10 with lots of room for movements. Plus it will spin into any Copal 1 shutter. It's a lucky find. But only for folks that actually make images.
 
I'd expect it to show up in bokeh highlights (changing their circular shape slightly) when shot wide open. But if you don't shoot this lens in a way that would create those, it wouldn't have an impact.
 
If you are going to use the lens with the crud in place then it may be a good idea to black out that part of the lens with a magic marker. The crud appears to be translucent and may lower the contrast of the lens. Blacking it out keeps diffuse light from the crud affecting the image.
 
I use G-Claron almost always with aperture closed way down (f/16 to f/64): since it aces in landscape or close-up macro. I don't remember I ever used it wide open. Thus even if the crud on the front rim remains, it will have minimal if any effects on image quality.
 
Thanks all. The first lesson I've learned is that whilst the crud might come off with careful cleaning, its not necessarily an impediment to making use of the lens as is. That's great.The longest LF lens I currently have is 210mm, so 240mm is useful.

I'm still locating lens cleaning fluid, but meanwhile, I tried my spare Copal 1 shutter. The rear element screws in perfectly. The front element has a thread dia. 38.82mm, and the female front thread of the Copal 1 is dia. 39.08mm. So it looks like the front element should probably fit, but it doesn't actually. The threaded flange at the back of the front element is approx 5mm deep, and the female thread at the front of the Copal 1 shutter is recessed about the same amount from the slightly protruded ring on the front, inside the shutter speed markings. This means that although the threads might be compatible, they can barely reach each other to engage.
 
Photos attached to illustrate the previous post.
 

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Update! I removed a plastic insert that was fouling the entry to the shutter. The front element now sits into place, but the threads are clearly very slightly smaller than the front female thread of the Copal 1 shutter. I could probably put something soft and rubbery in between to make it snug.

G-Claron retaining ring internal Dia. approx. 38.13mm.
Copal I front thread internal Dia. approx 39.12mm

So there is approx. 1mm of looseness between the front element and the Copal 1 shutter front thread.
 

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Last edited:

Check total length of the lens in barrel and in shutter.
 
Housing front ring to back ring:

In Barrel - 53.49mm
In Shutter - 69.30mm
 

Isn't it supposed to be just the front and rear glass cells of the G-Claron lens that are removed from the lens and then screwed into the front and rear of the copal shutter respectively?
Not the whole G-Claron lens aperture unit?
 
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