Best kit to get high quality pictures in surgery

[orthopod]

Hi All

This picks up on a thread i started a fair while back and for various reasons have never been able to follow up on.

I need to take high quality pictures during surgery (I am a specialist veterinary surgeon and need good pictures to illustrate lectures). I will typically have a non-sterile assistant to take the pictures. The camera will need to be around 30-50 cm from the surgical field, and the field of interest will be typically between 5 and 30 cm in length.

I have an EOS 7D body and was looking for a recommendation for a lens and light source. Previously the EFS 17-55 zoom was recommended alongside a MR14 EX ring flash. As i understand it, this ring flash will fit onto many lenses using macrolite adaptors, but these only go up to 72 mm and the 17-55 has a 77 mm filter size. Could i attach the flash to this lens somehow, and would it cut off the peripheral parts of the image? Is this lens still considered the most appropriate or has something better come along. I am wary that one day I might upgrade to a full-frame sensor but that won't be for some time, so happy to consider EFS lenses if they are better suited to my requirement. A lot of the zooms i was thinking might be suitable (24-105 and the 24-70) also have 77mm filter sizes

Thanks

[C4RBON]

Based on your subject size and camera distance, you need a lens that covers 6 deg (5cm area of interest at 50cm distance) to 54 deg (30cm area of interest at 30 cm camera distance).

On the wide end, you need 22mm for an APS-C sensor to frame your subject horizontally. For a Full Frame camera, you need 35mm. On the long end, you need 210mm to frame your subject horizontally for APS-C, and 340mm on a full frame.

30 cm is fairly close to be taking pictures; minimum focus distance is a real concern for many lenses.

Based on your requirements, I think the 24-70mm f/4L IS USM is the best choice.
- 24mm on the wide end is almost wide enough for your 30cm subject at 30 cm camera distance for your 7D. Hopefully moving the camera back a few inches won't be a problem.
- This lens has 30cm min focus distance, which is important for your application. The 24-105 f/4L IS USM (version 1) has a min focus distance of 45 cm. The 17-55mm has a min focus distance of 35 cm.
- Macro mode. This reduces the min focus distance to 20cm and increases the magnification to 0.7x.
- Full-frame compatible, if you ever get a full-frame camera. It is also a really nice general purpose lens, if you ever want to use it for other things.
- It's an L-series lens. Top-notch quality, durability, etc.
- It is $900 new, vs $830 for the 17-55mm f/2.8.

On to lighting...

Could you use a speedlight with a Rogue FlashBender? You could even get a coiled TTL cord to hand-hold the flash off-camera.

[orthopod]

Thanks for that, the information is very useful and that lens would be within my budget. Regarding the lighting - I had not heard of the Flash Bender, but having looked at it i don't think it would be a practical option in the operating room - there has to be absolutely no risk of contaminating the surgical site, so the 'sail like' nature of the flash bender would be a concern i think. Is anyone aware of ring-flash options that might work or any other potentially better options given the filter size of the 24-70 zoom is 77, so I don't see how i could attach a MR14 EX, and even if i could, would the flash housing being attached directly to the front of the lens cause image cut off/vignetting with an APS-C sensor?

Thanks for everyone's time - nothing seems to be straightforward!

[Sheiky]

Hi there,

I have a few questions:

What do you use now?
Do you need the full 18MP of your camera for your presentations or would it be ok to crop? In other words, would the presentation be with static photos or would you "zoom-in" during presentations?
What's the lighting in the room like? Could you do without a flash?
Does it need to be a zoom?
I understand one of your assistants will take the photos, is he/she comfortable with a big camera/lens/flash combination? Does he/she need to take photos from difficult angles(maybe due to space restrictions)? And is he/she purely there for taking photos or with another task as well?

As for using the MR-14 on 77mm lenses. I believe this is possible by using a step-down ring on the lens, 77-72mm for example. Obviously it will block the lens slightly. When using EF lenses on your camera I doubt this will be noticeable. While I was typing this I decided to test it out so here are the results when putting a 77 -> 52 stepdown lens in front of a 82mm lens:

Vignetting Test 52mm on 82mm Lens by Jan Paalman, on Flickr

Vignetting Test 52mm on 82mm Lens by Jan Paalman, on Flickr

The squares indicate the 1.6 crop focal length of your 7D.
I guess one could safely say that you can decrease the lenses opening by quite a bit(30mm in this case) without noticing any changes using an APC camera. The lens used was a Tamron 24-70 on a 5Ds, this lens has an 82mm filter thread. PS: Please don't mind the subject or quality of the images, purely test-material.

As said, I don't know if you must have a zoom. I personally like simplicity and if you only get to use the combination for photography during operations I would go as simple as possible. If you can get away with it the 65mm macro might be a good option in combination with a ring flash.
If you need a shorter focal length then something like a 35mm F2 (IS) might be a nice option in a small package.

I hope my input is of some help to you. Personally I wouldn't mind using the 24-70 F4 either, especially if you'd use it outside the clinic as well.

Good luck,

Jan

[DavidEccleston]

If 35mm is adequate, there is the just announced EF-S 35mm Macro w/ integrated ring light. Check the 3rd image on the B&H product page to see the ring light. I won't link to B&H here as I won't have the Bryan's referral code in the URL, but just search for "Canon 2220C002"