Minimal magnification

[Airborne]

Hello everyone! I tried searching the forum for this problem but can't seem to find a similar question posted previously. I hope you can figure that out.
I have run into a strange problem, namely I am not able to produce prints smaller than 18x18cm (about 7X7").
I use a Kaiser V-System enlarger for formats up to 6X7 and shoot 6X6. The original lens was a 50mm. As it could not cover 6X6, I got a rodagon 105/5,6. Now the problem: the new lens illuminates the whole negative, however I am only able to go down to about 18X18cm print size - the enlarger head won't stretch any further (it's already stretched about 20cm). I would like to make prints on 10X15 paper- can you please advise?

Regards,
D

 

[John Koehrer]

You're going to need more extension. You may have to fabricate an extension tube or box to get it. I don't know if Kaiser made anything like this.
Another option wold be a longer focal length lens.

 

[Monophoto]

Try elevating your easel - put a paper box underneath it.

 

[Nick Zentena]

I wonder if the enlarger is intended for an 80mm lens.

 

[ic-racer]

I interpret the original post as a lack of bellows draw. Try Monophoto's tip and see if that works, if not, then, indeed it is lack of bellows draw.

In that case, a longer focal length lens will make the situation worse and a wide-coverage lens like the Rodenstock Rodagon-WA 60 mm f/4,0, which covers up to 6x7 should be able to focus OK. (Or even an 80mm as, Nick suggests).

Also, if it is lack of bellows draw, then John's suggestion of an extension is very good.

Try to find or make some kind of cone like this: http://www.ritzcam.com/catalog/images/Omegaconer.jpg

Or like this, but flip it around so it extends outward rather than inward: http://www.largeformatphotography.info/forum/showthread.php?t=41357

 

[luxikon]

With my 50, 80 and 105mm Rodagon lenses I can use the normal extension tubes used in macrophotography.

 

[Martin Aislabie]

I think what you are saying is you are running out of bellows draw on the 105mm lens?

This is probably a physical limit of the bellows/enlarger

Can you put the 50mm lens back in and see how small you can go with it ?

A 50mm lens needs 50mm of bellows extension to got to 1:1, a 105mm lens needs 105mm to get to 1:1

Martin

 

[Airborne]

Thank you all for the quick replies.
I have indeed run out of bellows extension. With a 50mm I can go down to 1:1,5 or so, but the corners are not illuminated. Unfortunately things are as bad as I though- either I'd need some extension tubes or I will print in larger sizes.

Cheers,
D

 

[MattKing]

My theoretical optics knowledge is very rusty, and the design of the enlarger may not permit this, but instead of lowering the lens using extension tubes, can you accomplish the result you are seeking by raising the negative holder (putting something underneath it)?

Matt

 

[Nick Zentena]

Measure the distance from the negative stage to the lens stage. Somebody who remembers can post the exact formula but you need 2x focal length for lifesize. But of course you don't use an enlarger for life size. You'd contact print if you wanted that.

A shorter lens might solve your problem. Measure and that will show if a common 80mm would work.

 

[MartinP]

If you decide to go with extension tubes for a 39mm mount lens, then you could look on that auction site for extension tubes for the early Former Soviet union slr's. There would be no need to get something made specially by the manufacturer of your enlarger costing four times the price....

 

[Martin Aislabie]

Thank you all for the quick replies.
I have indeed run out of bellows extension. With a 50mm I can go down to 1:1,5 or so, but the corners are not illuminated. Unfortunately things are as bad as I though- either I'd need some extension tubes or I will print in larger sizes.

Cheers,
D

To enlarge a 6x6 or 6x7 Neg you need a 80mm enlarging lens to cover all the way out to the corners.

However, some Lens Manufacturers do/did Wide Angle Enlarging Lenses - I think at 60mm WA would cover a 6x7 Neg.

So you have 3 choices

1) Print larger paper sizes

2) Buy a 60mm WA Lens & still need to go to slightly larger paper sizes

3) Find some 39mm extension tubes or sacrifice one or two of the lens mounting cups and build yourself your own bellows extension tube - if you do this be careful to avoid vignetting in the corners

I have a Kaiser V - they are a nice enlarger - but I have never tried to print anything smaller than 10x8 with mine

Good luck

Martin