97 replies to this topic

[wahlaoeh]

I use a Nikon AF-105-VR almost exclusively. It has a 6-7" working distance (Distance from the end of the lens) to get 1:1. A subsee adapter will give 2.25:1 at a workind distance of about 3", somewhat less if you back up just a bit.

Here is a Bubble Coral Shrimp at more than 1:1. It is full frame. (I am not sure of the actual magnification but it is better than 1:1.) What is nice about this shot is that it is still a shot of the critter and the environment,

Thanks Tom. Nice shot! I have a Nexus CL-100 wet mount close-up lens that works fine with the 105mm when shooting objects that do not move much but limits the distance when I'm shooting skittish fish, like goby and blenny. That's why I'm thinking of getting the teleconvertor (double the magnification w/o limiting the lens distance from the object).

[Paul Kay]

To add a bit more to this thread. I've experimented a little with extension tubes and Canon macro lenses. My observations (above water) are:

The 60mm EFS lens is excellent on full frame Cameras with a 12mm extension tube added. Adding more (the 25mm extension tube for example) results in degraded image quality. This appears to be because the lens is of internal focus type and actually shifts focal length when focusing and is not optimised to throw an image significantly far from the normal image plane. So its not really usable with more than 12mm of extension.

The 100mm usm is of similar design but seems able to take greater extension - I've tried it with 37mm of extension so far and quality is still excellent. Whilst of similar internal focus design it is of longer focal length so there looks like there is more leeway in variance from the normal image plane.

So essentially, neither of these lenses will operate well if extended significantly which may be useful to know.

FWIW older lenses such as the 60mm micro-Nikkor will operate well with significant extension, but this in itself reduces their usefulness underwater as they have to be more or less fixed in a pre-determined magnification as gearing and porting them is impractical.

[TomR1]

I ordered a 2:1 Teleconverter that does autofocus on the AF-105-VR. It should be interesting to compare my results with the Subsee +10. My logic is that you lose a couple of stops with a 2:1 teleconverter but with the Af-105-VR I am typically shooting a couple of stops above F/11.

I'll let you know.

[Paul Kay]

I tried some real world testing on Saturday - the Canon 100mm usm macro combined with 1 x 25mm extension tube and 1 x 12mm extension tube giving a total extension of 37mm. I haven't sorted the RR but will do so. However, looking at the images on a 5D2 I can say that whilst there is greater magnification, the image quality at an indicated f/22 has dropped in comparison to the lens alone (to be expected but this simply confirmed it) and I suspect that interpolating a file taken at 1:1 would yield the same data. IF lenses such as this one do not produce particularly good results when placed further away from the image sensor. I also suspect that shooting the combination through a thick glass port is not helping either.

[TomR1]

I did some testing of my new Af-105-VR, Kento 2:1 TC combination on land. One would think that the image would be degraded because the light is spread over 4 times the area by the TC. However, in macro an increase of strobe intensity (actually duration) of two stops gets the combo back to even. I think there is very little image loss due to this.

What I find most interesting is to shoot somewhat behind the minimum focus distance. Essentially I am shooting ar greater that 1:1 but less than 2:1 at an increased working distance. Focus is relatively good even in available light. Just let autofocus do its trick (very difficult to get access to the manual focus ring underwater), then rock a bit. Basically I think I will be able to take high magnification shots of skittish critters at increased working distance. In clear water my two INON Z-240 strobes give me solid lighting at 18-24"

I think I will need a focus light to get proper focus as I try minimum working distance-maximum magnification. I have not tested this yet.

Tom

[bmyates]

I just returned from my Cayman trip (full gallery here), and while there tried the new Canon 100mm IS lens with the Kenko Pro 300 3X TC on one dive. AF was only useful in getting the focus in the general area of the subject, and then I had to use MF to fine-tune, but I didn't find that a significant impediment, since that's how I shoot macro normally (I've removed AF function from the shutter button).

While I was reasonably satisfied with the TC results, I wasn't overwhelmed. Here's an example:


I was able to get similar detail and sharpness (seems just slightly sharper) with the 100mm by itself, albeit with far more cropping:


These don't look too different (to me) in terms of detail. The difference is that the first photo represents about half of the original RAW frame, whereas the second only represents about 1/10 of the original frame. With 21 megapixels to work with (5D Mark II camera), severe cropping like that is possible, but the 3X TC (the first photo) definitely has advantages in terms of (a) preserving pixels, and (b) more working distance.

Thus, the primary advantage of this setup seems to me to be the ability to shoot macro subjects and fill more of the frame at more of a distance with less cropping. The 100mm IS by itself (like the old 100mm but with seemingly slightly faster AF) does a great job, but I can envision using the 3X TC in situations where I know I'll be photographing skittish little subjects and need to keep my distance.

[Paul Kay]

My problem is, I feel, that the fine detail in the images is 'softening' and comparing a 1:1 shot with the 100 usm lens alone with one from the extended lens shows that the shot from the extended lens will take less enlargement before the loss of definition in the fine detail becomes apparent. So I don't really think that using extension tubes is actually producing any more information so I might as well crop the 1:1 image instead. For much of my photography, working distance is less of an issue and what I am trying to do is increase the actual in camera magnification whilst retaining AF. I use a Kowalski Xenon as a focus light so AF is generally not a problem even with extension tubes. Has anyone got any suggestons?

Edited by pgk, 11 June 2010 - 09:12 AM.

[TomR1]

Bruce-

My understanding that the 3x really doesn't auto-focus very well but the 2x does. I find that I do need to rock a bit, however but not significently. I agree that the main benefit is more working distance for shooting skittish subjects like a Jawfish with eggs (nice shot)

Tom

[JJ4DIVER]

Anyone use the +10 Subsee diopter on the Nikon 105 VR lens?  Good results??

[TomR1]

I use the subsee +10 with the af105Vr all the time.

 

The first problem I have is finding the subject. There is a very small in-focus window and I am forever looking for the subject. My solution is have my buddy shine a small flashlight on the subject. I can follow the light to the subject.

 

The second problem is getting focus. I shoot in focus priority which means that the shutter wort release unless the lens is in focus. I move to closer that minimum working distance, then back up until the subject comes in focus. In any surge focus is difficult on my D-300.

 

However, if it works, great shot.

[rumblefish]

so how would a 180mm macro (Sigma) work with a +10 diopter? Minimal working distance for the Sigma is 50 cm. 

--Rob

[whaleshark]

I've found that a teleconverter does not add magnification but it increases the focal length and working distance. The mimimum image size is the same but you can achieve it from farther away. A 1.4 teleconverter reduces the light by one stop. A 2x reduces the light by two stops. Teleconverters generally don't work well on slow lenses but do work on f/2 and f/2.8 lenses. They reduce image quality, but not significantly on the faster lenses.

You have plenty of light with dual strobes so small apertures with a TC at macro distances are not a problem. No one wants to shoot macro wide open because of the negative affect on DOF. It just gets harder to autofocus when the minimum f-stop drops to around f/5.6 or f/8. Otherwise reducing the aperture is really not an issue for UW macro.
I'm shooting macro with the Olympus E-330 in an Ikelite housing and the 50 mm f/2 macro lens (100 mm equivalent). It provides 2:1 macro which is a 34 by 26 mm minimum image size. On Olympus 4/3 format, using the 35 mm f/3.5 macro lens allows 1:1, or an 18 mm by 13 mm subject size. That's a really small image size. For topside wildflowers and other macro I use the the E-5 with the 50 mm lens and a flash ring.

The 50 mm macro achieves 2:1 at a reasonable working distance, several inches away. The 35 mm macro lens achieves 1:1 at about 1" from the lens, or right at the lens port face. That's not useful underwater, but you can still focus the 35 mm macro at less than 1:1 magnification from farther away. The 50 mm is a better lens for UW macro on Olympus 4/3.
The 2:1 macro image size on 4/3 is essentially equal to what the full frame camera achieves at 1:1. The 4/3 sensor is only a little bit smaller than the APS-C sensor size. Apart from recent advances with newer APS models in high ISO and DR, the IQ and functionality is similar. For macro UW with strobes shooting at low ISO is typical so the differences are marginal.

An extension tube increases magnification without reducing the light. With the 50 mm f/2 macro and the EX-25, a 25 mm extension tube, it achieves 1:1 from a closer distance. In-focus range is limited to between 2" and 4" with the lens focused from minimum distance to infinity. I've used this combo a lot topside with a ring flash and the image quality is great. The subject size is as small as 18 mm by 13 mm with the Olympus 4/3 format.

For UW macro here are the downsides to using this 50 mm + EX-25 combo (and probably with any system): It's very hard to find subjects within the focus plane at that magnification. Everything is a blur until you bring the subject right into the focus distance. Autofocus is awful unless you're already close to correct focus. If you're too far away for the lens + EX it will never achieve focus. Shooting topside with the EX-25 I typically manual focus at anywhere from minimum to infinity and then move in until I achieve focus. It may be possible to arrange the Ikelite zoom ring to function as a focus ring even with the EX-25 in place. I put the zoom ring on the focus ring for both the 50 mm macro and the 8 mm fish eye lens since there is no zoom and it works well but you can not see the focus scale. For UW behind a flat port the 50 mm + EX may be far enough away At the available focus distances, but strobe lighting will be difficult.

I've found the Olympus 50 mm f/2 macro lens to be very capapble for UW macro. I haven't had any desire to increase focal length with the EC-14 because the 50 mm is far enough for most subjects. It's also challenging enough to aim and focus with just the lens so I'm not ready to make it more diffficult with a longer focal length.

As other people have said, I think achieving greater magnification than 1:1 underwater is probably better with a longer focal length. I may try this using an extension tube with the Sigma 105 mm or Sigma 150 mm f/2.8 macro lenses.

[TomR1]

I tried a Sigma 150mm lens on my Nikon D-300. It did not gain me any working distance. The minimum focus distance is longer on the 150 than the 105 but the lens is almost exactly the same amount longer. The lens is slow autofocus and I am used to the quick AF-105-VR's characteristics. The lens is going on ebay.

 

I intend to revisit the Kenko 2:1 TC on my Nikon Af-105-VR. Previously I could not properly house the 105/diopter. The combination port's (needed for the 150/tc combo) internal diameter is smaller than the single piece port I use without the T/C. I solved this problem with my Sigma 150 by removing the switch assembly on the side of the lens. I will try the same with the 105.

 

I need to shoot in autofocus because I don't have a focus ring on my port. 

 

I will try this idea in my pool and post shots.

 

Tom

[Glasseye Snapper]

so how would a 180mm macro (Sigma) work with a +10 diopter? Minimal working distance for the Sigma is 50 cm. 

--Rob

 

The maximum working distance (from tip of lens to subject) goes from infinity without diopter to 20cm for a +5, and 10cm for a +10 diopter. The +5 with a 200mm lens focused at infinity, achieves about 1:1 magnification with the subject 20cm in front of the lens. For the +10 magnification will be higher. When focusing the lens to its minimum distance magnification will be well  beyond 1:1 and focus distance well below 10/20 cm in front of the lens, but unless you want to do the math it is easier to just try it out. In all cases the apparent aperture remains the same but you obviously get a significant reduction in DOF. You can stop down the lens a lot more to gain DOF but you will loose the extra detail you worked so hard to get with the diopter. Best use the diopter for flat or tiny objects where a few mm DOF is all you need.

 

Bart

[Glasseye Snapper]

I tried a Sigma 150mm lens on my Nikon D-300. It did not gain me any working distance. The minimum focus distance is longer on the 150 than the 105 but the lens is almost exactly the same amount longer. The lens is slow autofocus and I am used to the quick AF-105-VR's characteristics. The lens is going on ebay.

 

I intend to revisit the Kenko 2:1 TC on my Nikon Af-105-VR. Previously I could not properly house the 105/diopter. The combination port's (needed for the 150/tc combo) internal diameter is smaller than the single piece port I use without the T/C. I solved this problem with my Sigma 150 by removing the switch assembly on the side of the lens. I will try the same with the 105.

 

I need to shoot in autofocus because I don't have a focus ring on my port. 

 

I will try this idea in my pool and post shots.

 

Tom

Working distance (distance from tip of lens to subject) as well as the distance from the sensor to the tip of the lens is approximately 2 times the focal length of the lens when you are at 1:1 magnification. At infinity, your lens has a focal lens of 105mm. However, internal focusing lenses are less than 2 times their focal length long and where older lenses extended their lens barrel, internally focusing lenses cheat to obtain their minimum focus distance by reducing the focal length (in effect it acts like a zoom lens). Still, the 150mm lens at 1:1 should give a larger working distance than the 105mm lens, although the difference may be less than the 9cm or so you would have expected. You get more bang for your buck from the 150mm lens when considering magnification boost compared to the 105mm lens when shooting at longer distances.

 

Bart

[TomR1]

Bart-

 

Yes the 150mm lens has good magnification shooting skittish fish about 1-2 feet away. However, the slow autofocus seriously detracts from taking those shots.

[rumblefish]

Thank you Bart, that is very useful info. 

Yesterday, I experimented with my 180mm macro and a reversed 50mm on top of that and got decent results shooting a tiny spider in my garden (topside obviously).  Working distance a few centimeters, fiber snoot to get some light on it and dof half a mm at best. (see example below)

Attached Images

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Edited by rumblefish, 06 May 2013 - 10:46 AM.

[Glasseye Snapper]

Nice shot and it really brings out the DOF issue or benefit, depending on what you want to achieve with the image.

 

Bart