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Canon 24-70mm f/4

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Can anyone share their experiences using this lens underwater? I haven't seen it mentioned much, but with the zoom range and the close focus ability (up to 0.7x) it seems like a useful lens for macro work and fish portraits.

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Can anyone share their experiences using this lens underwater? I haven't seen it mentioned much, but with the zoom range and the close focus ability (up to 0.7x) it seems like a useful lens for macro work and fish portraits.

I used this lens during my most recent trip to Hawaii (in 2016) - there are a number of examples on my website in the Aloha! galleries. I used it with a Canon 500D diopter lens. It is a +2 achromatic which means it is fairly thick so there is tiny amount of vignetting at 24mm. I found simple one-lens diopters to be unsatisfactory. The minimum focus is 0.38m other than using it in macro mode which requires one to slide a switch. This makes the macro mode not useful for underwater use IMHO. I used the 24-70 with a Seacam Compact Port - my guess is that the port's radius is the same as an 8 inch hemispherical port. One can use this lens with a Superdome (it has a larger dome radius) and no diopter - see http://wetpixel.com/forums/index.php?showtopic=52222&hl=%2Bcanon+%2Bnorway.

Edited by Tom_Kline

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Thanks for the input. Too bad there's no way to switch between macro and normal mode underwater. Still seems like it has a useful zoom range. Did you have any issues optimizing for the entire zoom range? That is, are the optimal port extension and diopter similar throughout the whole zoom range, or do you have to pick one set of focal lengths to optimize?

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By the way, I'll be using this lens with an Ikelite 8" dome, so any experience with this particular dome would be especially appreciated.

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Thanks for the input. Too bad there's no way to switch between macro and normal mode underwater. Still seems like it has a useful zoom range. Did you have any issues optimizing for the entire zoom range? That is, are the optimal port extension and diopter similar throughout the whole zoom range, or do you have to pick one set of focal lengths to optimize?

I set up mine to work at 24mm. Optimizing for 70mm would involve much more port extension and thus severe vignetting at 24mm. The trouble with normal focal range zoom lenses is that they extend quite a bit when zooming. The 24-70/4 extends a bit less than the Canon 24-70/2.8 or 24-105/4 lenses see- http://www.the-digital-picture.com/Reviews/Canon-EF-24-70mm-f-4-L-IS-USM-Lens-Review.aspx(scroll down about 80% of the page).

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Reviving this old thread. 

Has anyone tried to use the Canon 24-70 F4 at the Macro end?   It wouldn't be full 1:1 macro, but it has much closer minimum focus distance which could be a benefit to avoid backscatter.  This is prompted by a recent wetpixel youtube where it was suggested closer focusing is of benefit.

Fully extended, the lens is about same length as 100mm F2.8, roughly same diameter so maybe even the same port could work. On a crop sensor it would even be full macro magnification.

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6 hours ago, pygmy_whaleshark said:

Reviving this old thread. 

Has anyone tried to use the Canon 24-70 F4 at the Macro end?   It wouldn't be full 1:1 macro, but it has much closer minimum focus distance which could be a benefit to avoid backscatter.  This is prompted by a recent wetpixel youtube where it was suggested closer focusing is of benefit.

Fully extended, the lens is about same length as 100mm F2.8, roughly same diameter so maybe even the same port could work. On a crop sensor it would even be full macro magnification.

You are talking about using a flat port and at the wide end the image quality will suffer and I am quite certain you would get vignetting as well due to the lens extending when zoomed to 70mm. 

If you are talking about using it as a macro lens locked in at the macro setting it has some disadvantages compared to a regular macro lens including the working distance being reduced to about 30mm at maximum magnification , which would leave you with about 20mm from the port glass if the port fitted perfectly.   You also lose infinity focus at that setting.  at 0.5x the the working distance is about 64mm, usable but less than you would get with the 100mm macro. 

The switch only acts to stop you accidentally zooming into macro range where the focus range is restricted.  It might be possible develop a system to keep the switch in the macro position so you could zoom into the macro area UW and use that system with a dome port. because you are focusing on the virtual image the loss of infinity focus would not matter, the very closest focus would be too close to the dome probably but you may improve the the max magnification at a reasonable working distance.

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59 minutes ago, ChrisRoss said:

You are talking about using a flat port and at the wide end the image quality will suffer and I am quite certain you would get vignetting as well due to the lens extending when zoomed to 70mm. 

If you are talking about using it as a macro lens locked in at the macro setting it has some disadvantages compared to a regular macro lens including the working distance being reduced to about 30mm at maximum magnification , which would leave you with about 20mm from the port glass if the port fitted perfectly.   You also lose infinity focus at that setting.  at 0.5x the the working distance is about 64mm, usable but less than you would get with the 100mm macro. 

The switch only acts to stop you accidentally zooming into macro range where the focus range is restricted.  It might be possible develop a system to keep the switch in the macro position so you could zoom into the macro area UW and use that system with a dome port. because you are focusing on the virtual image the loss of infinity focus would not matter, the very closest focus would be too close to the dome probably but you may improve the the max magnification at a reasonable working distance.

 

I'm talking about locking it in Macro mode, and using it strictly for that.  And the reduced working distance is the whole point if you see my comment. It's to reduce the chance of particles in the water between the subject, which is often a problem on night or blackwater dives.

 

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1 hour ago, pygmy_whaleshark said:

 

I'm talking about locking it in Macro mode, and using it strictly for that.  And the reduced working distance is the whole point if you see my comment. It's to reduce the chance of particles in the water between the subject, which is often a problem on night or blackwater dives.

 

yes I know decreasing working distance is good but at some point it becomes difficult to light the subject and 20mm is in the difficult territory.  I found one review which reported length at full extension to be 130.8mm which may be marginal to fit in the 100mm macro port as the 100mm macro is 123mm long.  It might be worth playing with if you already had one, but I certainly wouldn't buy one for the purpose and it's now a discontinued lens. 

If you are on APS-C the Canon 60mm macro would be a better alternative with 85mm working distance at 1:1 (probably about 75mm in the port), an improvement from the 100mm macro which is 133mm at 1:1

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8 hours ago, ChrisRoss said:

yes I know decreasing working distance is good but at some point it becomes difficult to light the subject and 20mm is in the difficult territory.  I found one review which reported length at full extension to be 130.8mm which may be marginal to fit in the 100mm macro port as the 100mm macro is 123mm long.  It might be worth playing with if you already had one, but I certainly wouldn't buy one for the purpose and it's now a discontinued lens. 

If you are on APS-C the Canon 60mm macro would be a better alternative with 85mm working distance at 1:1 (probably about 75mm in the port), an improvement from the 100mm macro which is 133mm at 1:1

For blackwater, lighting isn't an issue since strobes can be put right on the sides of the port. Side lighting is best for most of the transparent critters anyway.

I do have the 24-70mm, hence I did all the sizing comparisons and at full extension it's maybe 5mm longer than 100m, but there's a range in the macro region of the zoom ring, where it can be made exactly same length.

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11 hours ago, pygmy_whaleshark said:

For blackwater, lighting isn't an issue since strobes can be put right on the sides of the port. Side lighting is best for most of the transparent critters anyway.

I do have the 24-70mm, hence I did all the sizing comparisons and at full extension it's maybe 5mm longer than 100m, but there's a range in the macro region of the zoom ring, where it can be made exactly same length.

If you have everything why not give it a go, blackwater diving is a special case I think.  The thing to check is how much infinity focus you lose, which you can easily check on land, I expect you need that to acquire the creature in the viewfinder and slowly close in.   I've not done blackwater diving, however the creatures are reported to be 1-2cm size for many of them and shy so small working distance could be a blessing and a curse. 

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8 minutes ago, ChrisRoss said:

If you have everything why not give it a go, blackwater diving is a special case I think.  The thing to check is how much infinity focus you lose, which you can easily check on land, I expect you need that to acquire the creature in the viewfinder and slowly close in.   I've not done blackwater diving, however the creatures are reported to be 1-2cm size for many of them and shy so small working distance could be a blessing and a curse. 

I don't have the housing for my Canon yet. I'm diving with RX100 for now but thinking of stepping up.  I brought this up to see if anyone already has used it and has pics to share, since I'm aware of all the technical details and pros/cons.

24-70mm has a few meters of max focus distance at the macro end, so it won't be an issue.

 

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24 minutes ago, pygmy_whaleshark said:

I don't have the housing for my Canon yet. I'm diving with RX100 for now but thinking of stepping up.  I brought this up to see if anyone already has used it and has pics to share, since I'm aware of all the technical details and pros/cons.

24-70mm has a few meters of max focus distance at the macro end, so it won't be an issue.

 

I don't expect it would be a common solution  used by many people.  It might work OK for blackwater but I don't believe it would be a substitute for a regular macro lens. 

There is probably no loss in trying it if you get the macro port for the 100mm as you could always get that lens later-  assuming you are on full frame, the 100mm is probably a bit long for APS-C. 

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