Temporary lens loan/exchange

Well, it just dawned on me, while I was out walking with the fur-child, that I should post this up on here... so here I am.

I've been thinking of getting a 105mm for my 4x5 kit for a while now, I've got a 90mm but it's just, 'wrong'. I never really liked 28mm lenses (in small format terms), which is about what a 90mm on 4x5 is roughly equivalent to. However, I find it easy to get inspired by something slightly wider or slightly longer, in my 645 kit this is the 35 & 55 (21 & 35 in 35mm terms), with this kit I could happily live even with just the 55. So, I decided a 105 could be a good replacement for my 90 (which hardly gets used).

So that got me thinking, maybe there's a local 4x5 user who has a 105mm I might be able to borrow for a weekend to see if it actually is what I'm after. I'd be more than happy to make a trade out of it, if there's anything I've got that you'd be interested in testing out (or, just taking as ransom really...). I've also got three lenses up on ebay at the moment, if any of these are something someone might like to get a hold of, I'd be happy to pull them down and just do a trade (or trade +cash, whatever works out.

Rodentstock 135mm

Rodenstock 180mm

And a Komuranon 90mm

Anyway, as I said, it was just a thought that came to me while out walking, so if anyone semi-local (to Melbourne) uses a 105, I'd be very interested to hear from you and possibly test drive your lens before I commit to shopping around and finding my own.

Cheers!

People seem to get it all 'wrong' when talking about 'lens equivalents' across formats.
Comparing 35mm with 5x4 especially and also the 'standard' lens for 5x4.

The 'Standard' lens for 35mm is somewhere between 50 and 55mm, right. Take the middle and call it 52mm.
This lens has, over the decades, been accepted as the standard because it has emerged as the lens which most closely approximates the field of view and perspective of the human eye.

Now, in comparing lenses across formats one uses the length of the diagonal across the rectangular image at the film plane.
the diagonal of the 24x36mm image of 35mm film is 43.25mm
and the diagonal of the 121x95mm image of 5x4 film is 153.85mm.

But that ignores the difference in aspect ratio of the two formats, so what we really should be using to characterise the 35mm format when we are comparing with 5x4 is a 30x24mm image having a diagonal of 38.4mm.

To find, therefore, what the 'standard' lens for 5x4 should be we multiply out 52*(153.85/38.4) ==> 208 mm

To find out what the equivalent lens in 35mm format would be for a 5x4 lens, multiply the focal length of the 5x4 lens by (38.4/153.85). A 90mm lens on 5x4 is therefore equivlent to a 22.4mm lens on a 35mm camera.

I've calculated the quivalent focal lengths of my 5x4 lens set below.
5x4 format 35mm format
65mm 16.25mm
90mm 22.5mm
135mm 33.75mm
210mm 52.5mm
300mm 75mm
NB: I don't actually have the 65 or 300 yet - but they're on the list!

This equivalence compares well with shooting experience. The 24mm in 35mm format and the 90mm in 5x4 format tend to be the widest one can use without gross wide-angle arifacts dominating the image.

PS: If you use the full 36x24mm fram on 35mm format for comparison the 5x4 'standard' lens would be a 185mm lens - I leave the calculation of other equivalents as an exercise for the student.

Peter.

I know the cross-format comparisons aren't quite right, but I've always found it a good 'rough enough' kind of comparison so that, say, if I happen across a scene and capture a nice shot, but want to return with a larger format, I know the rough ballpark lens to head for. I've always just gone with the quick 'x3' to compare 35mm to 4x5, and even though the maths might say otherwise, I've found it to be close enough, well, close enough for my uses anyway.

...that said, irrespective of what it might work out to as an exact comparison, I'd still like to have a play with a 105mm, from images I've been shown taken with that focal length, it seems to be a nice compromise position between, say, a 90 and a 135.

I don't know of many 105mm lenses for 5x4, I think Schneider might make one, new series though, and probably expensive. I personally quite like the 90mm, but also use the 135mm a lot on my Technika V as it still gives me a wide without having to drop the lens standard.
There are quite a few 100 and 105's that were made for the 6x9 format, won't work with your 5x4 setup though. Come to think of it, Topcon made a 105mm super back in the sixties, had a huge rear element and although made for 6x9, still just covered 5x4...good luck finding one of those though!
Tony

G'day tony,

I find the same thing, 135 is just a nice focal length for me, it feels (well, sometimes) as though compositions just fall into place, whereas I was always struggling with the 90mm. Shane (smbooth) ended up buying (stealing? :P ) it off me through ebay, I'm hanging out to see one of his shots with it, it'll just be interesting since I could never really get comfortable with it.