Enlarging lens question

[stevewillard]

I am currently assembling an 8x10 enlarger, and I was

wondering if I could use a 270mm lens for a 4x5 negative?

[armin_seeholzer]

Hi Stephen

 

Only if you have enough space between lens and paper!A standard lens for 4x5 is 150mm, 210mm for 5x7 and 300mm for 8x10 if I remember correctly! So it coud maybe work for 8x10 if it has enough coverage!

 

Good luck!

[neil_poulsen1]

The issues are the height of the column, the maximum distance that you can place between the lens and the nagative, and the height of your ceiling. When considering what lens to purchase for my 8x10 enlarger, I constructed a spreadsheet to consider these questions. Here are a couple of sample calculations. Note that a 240mm lens can also work with 8x10, like a 240mm Componon-S.

 

Considering a 4x enlargement (e.g. 4x5 to 16x20) with a 240mm lens, you must have 11.8" between the lens and negative, and your column and ceiling must allow 59.1 inches between the negative and the paper. With a 270mm lens, these numbers would be 13.3" and 66.1" respectively.

 

For a 6x enlargement (e.g. 4x5 to 16x20 w/cropping) with a 240mm lens, you must have 11" between the lens and negative and 77.2" between the negative and paper. For a 270mm lens, these numbers become 12.4" and 86.8" respectively.

 

For a 2.5x enlargement (e.g. 4x5 to 8x10 with cropping) with a 240mm lens, you must have 13.2" between the lens and negative and 46.3" between the negative and paper. For a 270mm lens, these numbers become 14.9" and 52.1" respectively.

 

On the other end, for a 1.5x enlargement (e.g. 8x10 to 11x14), you must have 15.7" between the lens and negative and 39.4" between the negative and paper. For 270mm, these numbers become 17.7" and 44.3" respectively.

 

Etc.

 

Probably the most important consideration is the maximum distance that your setup allows between the negative and the paper. Depending on the lens and enlargement, these distances can get huge. There's also a significant improvement in using a 240mm lens versus a 270mm lens. Column and ceiling heights not withstanding, how long are your arms? You have to be able to focus the silly thing, too!

 

If these calculations are useful, let me know if you want others. I would need the enlargement and the focal length.