Join the conversationon Joe Cornish – Reader’s Questions
These interviews and Q&A podcasts are not only very enjoyable in their own right (like listening to a radio discussion), but also excellent to listen to while scanning or post-processing images. Thanks Joe for introducing the two wildlife photographers you mentioned: they produce different but equally inspiring and unusual work. Adam [...]
- Adam Pierzchala, 22:12 11th Febon Put Your Questions to Hans Strand
Yes, medium format will have a tough future. Though there are still people (including myself) who think it is worth the extra cost to get an extra edge. The difference is more obvious when you make large prints. A one meter wide print from medium format will convince you about [...]
- Hans Strand, 20:37 1st Febon Samantha Gibbons
Hi Samantha, it was great to see your images and to read how you feel about photography! I like what you say, "how beautiful the landscape around us really is.. It’s almost religious", as I feel almost the same! Your vistas have this subtle but intriguing light but I also like [...]
- Beata Moore, 10:09 30th Jan
A look at lens 'shift' with DSLR cameras
Tim Parkin
Your humble editor, ex-mathematician, A&R for U2, web developer to the Queen, guitarist and general geek-boy.
Other articles by Tim Parkin
Most people are familiar with the way that a shift lens can ‘fix’ the perspective (verticals) in buildings or trees, even if they haven’t tried these lenses themselves. How these lenses work is often not completely clear and even those with experience typically don’t know how to make the most of them. Hopefully this article can make things a bit clearer.
The first thing that most people learn about creating pictures with ‘correct’ verticals is that the camera shouldn’t be pointed up or down but straight ahead. Let’s imagine we are working with a 24mm lens and that we’re taking a picture of a tower block. The only way we can get the tower block in is to point the camera upwards but that gives us a distorted view as shown below..
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“6×7 is two times larger than 35mm ”
A minor correction but it’s actually more than 4.5 times the surface area.
35mm film is 24*36mm = 864mm2
6*7 film is (at least on the Mamiya RZ67) 59mm * 67mm = 3953mm2.
3953 / 864 = 4.57
Hi Kevin, I did my calculations on some of the 6×7′s I’ve been scanning by different people which have averaged 56mm x 69mm but that still gives a 4.47 difference. However my reference to 2x was in terms of linear dimension and I was using the longer edge. 36mm for your 35mm film vs 69mm for 6×7 film which is more or less two times. Taking a more accurate average, the linear dimension difference is probably 2.1x — thanks for pointing things out though – given that this difference is the same as that between an 18megapixel camera and a 21megapixel camera – people would definitely see that as significant!
I understand now that for your purposes, ie looking at shift, that the linear dimension is more relevant; whereas if the object was to look at the potential for improved image quality then the surface area would be relevant.. Your 6*7 dimensions is correct as I was going from memory.
It still amazes me that some people (encouraged by the printed photo press) think that the purpose of tilt and shift is to produce a “toytown” effect …
Great article Tim! It is for articles like this that I subscribe. More articles that teach us more about and help us get the most out of the equipment that we use please.