Rodenstock 180mm Macro

[matt_bennett3]

Hi Guys,

 

First post on here as I am a new LF user and have not even received my gear

yet. My question is, will the movements on my new Toyo View 45AX (I think

about 320mm max extension) limit what I could do with the new Rodenstock 180mm

f/5.6 Apo-Macro-Sironar or is it more advantageous to get the longer macro

lens (as opposed to the 120mm say) for increased lens-object working distance?

I think I've been a bit confused by all the formulae on here and thought the

macro lenses were maximised for sharpness at bellows extensions of around

their focal length (1:1)? Thanks in advance.

 

Matt

[michael_briggs2]

Most of the dedicated LF macro lenses are symmetrical and therefore optimal at 1:1 and excellent over some reproduction range N:1 to 1:N. The Rodenstock Apo-Macro-Sironar is the exception. Rodenstock sensibly thought that LF photographers are more likely to take photographs of objects of say 10 or 20 inch size than they are sub-inch size -- so they biased the lens design in this direction. The Apo-Macro-Sironar is not symmetrical. The recommended range is 2:1 to 1:5.

 

With an extension of 320 mm, you will be able to focus to about 410 mm subject distance, which is magnification 0.8, just shy of lifesize (1:1). (I say "about" because I haven't allowed for the offset of the rear principal plane from the lensboard, but this will be a small effect.) 1:1 with any lens requires an extension of twice its focal length, obviously 360 mm for a 180 mm.

 

The 180 mm lens will give you more working distance to the subject, which can help with lighting the subject. It will also give you a larger image circle for more movements, such as tilt and swing for adjusting the plane of best focus. The 120 mm focal length would allow you to do lifesize imaging, and beyond. So if you are buying only one macro lens, you have to decide what is more important to you.

[matt_bennett3]

Thanks Michael. I see where I went wrong. Think I'll prob stick to the 180mm for better lighting options, my outdoor/nature needs probably don't call for much more than 1:1 and the format allows for quite a bit of enlarging anyway. Cheers.

 

Matt