Extension tubes & lighting

[a_venk]

<p>Hello!<br>

I'm new to PN (but have a few years' experience with film and digital photography). I am putting together a simple set-up for the macro photography of static subjects, and am posting here with a few questions that I haven't readily been able to answer from the information already posted on PN.<br>

I will be using D200 or D7000 bodies, and manual extension tubes with 28mm f2.8 or 50mm f1.8 MF AIS lenses (neither is a macro-focusing design). I expect to need reproduction ratios ranging between 1:4 to about 4:1.<br>

(1) Can anyone recommend inexpensive (say <£25) manual extension tube sets that will provide the ratios I need? I am based in the UK and have found manual extension tubes sold by SRB Griturn [http://www.srb-griturn.com/manual-extension-tubes-1246-p.asp] but the tube sizes are not listed, so if anyone has used this type before, it would be helpful to hear from you.<br>

(2) Is it advisable to reverse-mount the lenses, particularly when my working distance lens->subject is less than the sensor<-lens distance, and if so, why?<br>

(3) I would ideally like to use off-camera strobes for lighting my subject. Will it be possible to trigger off-camera strobes using the pop-up flash as commander, given that the camera will not detect the lens via a manual extension tube? I reckon I won't need iTTL metering with the flash, since my subjects will be static, and I can find the right exposure by trial and error, but please correct me if my thinking is wrong.<br>

There's clearly a lot I need to learn concerning lighting for macro photography, so I'd appreciate links to any guide covering this topic.<br>

Thanks for your help.</p>

 

[kohanmike]

<p>This is probably an aside to your question, but here's the macro setup I use; D300s with a Tamron 60mm f/2.0 macro lens for 1:1, and trigger the two SB600 flash units with the commander in the camera, iTTL set for 1/2.</p><div></div>

[jeannean_.]

<p>You might like to visit the following links to see the variety of ways people accomplish what they want to do. Many times, it's experimentation, but seeing what others have done or are doing, helps get you started:</p>

<p><a href="http://www.fredmiranda.com/forum/topic/780820">Set-ups for macro</a></p>

<p><a href="http://www.fredmiranda.com/forum/topic/1001614">Shooting with tubes</a></p>

<p><a href="http://www.fredmiranda.com/forum/topic/663112">Reversing lenses</a></p>

[jose_angel]

<p>New extension tubes use to be expensive (way more than 25GBP), while some used ones are offered for reasonable prices, you should look at second hand listings or ebay...</p>

<p>If you`re looking for 4:1 with the 28/2.8, you`ll need more than 100mm of extension with the lens reversed. I think an straight lens will not reach that magnification. With the 50/1.8 the extension needed will be even longer, more than 200mm to reach that 4:1.</p>

<p>Think that 4:1 is an extremely high magnification, where the lack of DoF is the main characteristic... and you`ll not only need something to provide that extension, but a good complete setup including a focusing rail.</p>

<p>If I recall it correctly, the PK-13 provide 37.5mm of extension, the PN-11 is about 52.5mm. You can make an idea of the gear needed... two or three stacked tubes for the 28, a few more for the 50.</p>

<p>A macro bellows seem to me a much better idea. The Nikon latest one provide a bit more than 200mm, just what you need for 4:1 with the 50. I think the 50/1.8 will provide better results than the 28/2.8 reversed.</p>

<p>Nikon use to recomend for better results to use the smallest aperture on straight lenses, f8 if the lens is reversed. The main problem about reversed or not is the reach... for 4:1 with the 28 the only way is reversed. With the 50mm is the opposite, the only way is straight, although reversed goes closer that size.<br /> And, I think it was Rorslett who said that macro setups should be tested for performance, there are no rules...</p>

[jose_angel]

<p><em> "Is it advisable to reverse-mount the lenses, particularly when my working distance lens->subject is less than the sensor</em><br /> Theoretically and basically, "if the working distance is smaller than the bellows extension", you are over 1:1 magnification ratio (leave it this way). In this case reverse mounting an assimetric lens is advisable to keep the lens` aberration correction.<br /> ---<br /> BTW, <em>"Nikon use to recomend for better results to use the smallest aperture on straight lenses... "</em> I wanted to mean not "the smallest" but<em> smaller</em> apertures; diffraction is of an issue here too.</p>

[a_venk]

<p>Thanks for your responses, Michael, Jeannean and Jose, and for the useful information.<br>

I can see that 4:1 is going to be difficult just using extension tubes, and will try to stay nearer 1:1 or 2:1 reproduction ratios. A macro bellows would be great, but is out of my budget for the moment.<br>

A few remaining issues further to the responses above:<br>

If anyone has experience with the SRB Griturn manual tubes [http://www.srb-griturn.com/manual-extension-tubes-1246-p.asp]: are the sizes sufficient for 50-100 mm of extension?<br>

Is there a formula to estimate the reproduction ratio when reversing lenses?<br>

When using a manual extension tube or reversed lens with the D200 or D7000 body, will it be possible to trigger off-camera strobes using the pop-up flash as commander? I assume the camera will not detect the lens, but cannot figure out whether the CLS system or iTTL metering will work in manual mode with this setup.<br>

Thanks for your help.</p>

<p> </p>

[jose_angel]

<p>No experience with that tubes. You should ask the seller for the maximum and minimum extension with this tubes. You could find that the shortest combination is simply too long, or the longest too short. Again, I have not info about this set.<br /> The best way to know the reproduction ratio of a given lens (Nikkor) is to check the Nikon charts; just search for e.g. the PB-6 user manual (Butkus has it). In the latest pages you`ll find that chart with all the info you need for the most common lenses. I think you could calculate it for symmetrical lenses, but for assymetrical ones it could be quite difficult...<br /> I`m sorry I don`t have your cameras, but I understand you can use your pop-up flash to trigger the strobes. Another topic is if it will work iTTL, without a chipped lens, or whatever... I don`t see why not a pop-up flash will work in manual mode even without a lens, but I cannot confirm this.</p>

[sem_svizec]

<p>> If you`re looking for 4:1 with the 28/2.8, you`ll need more than 100mm of extension with the lens reversed. I think an straight lens will not reach that magnification. <br>

But this should work just fine, with a reversal ring (BR-2A) and el-cheapo extension tubes from hongkong. Notice reversed primes should work better on some extension. Preferably at least to their min focus distance - but mind the effective aperture gets small by then wide-open, leading to diffraction softening, and stopping down a bit to avoid lens shortcomings at its max aperture may soften images even more. Only short macro primes are desiged to work fine reversed without much extension - check old 55/3.5 micros, good and admirably inexpensive. For best performance, the lens should be focused to the flange distance (where the sensor was supposed to be). <br>

Automatic extension tubes like Kenko are recommended when the lens is not reversed, mainly because you get automatic aperture for easier aiming and auto metering. <br>

(2) Is it advisable to reverse-mount the lenses, particularly when my working distance lens->subject is less than the sensor<-lens distance, and if so, why?<br>

Adding extension you are running out of working distance, you get max magnification as focus hits the glass. Turning the lens around you reverse the reproduction ratio, so with a short lens you can reach higher magnifications (but long teles are not good for this). <br>

> (3) I would ideally like to use off-camera strobes for lighting my subject. Will it be possible to trigger off-camera strobes using the pop-up flash as commander, given that the camera will not detect the lens via a manual extension tube? I reckon I won't need iTTL metering with the flash, since my subjects will be static, and I can find the right exposure by trial and error, but please correct me if my thinking is wrong.<br>

Yes this should be fine. But for the start you can try just the pop-up flash with a paper hanky ten cm in front of it for diffusion, or some similarly translucent plastic dish mounted at the end of the lens. </p>

 

[a_venk]

<p>Thanks for the further information, Sem and Jose. I now know what I will need to get started!<br>

If anyone out there has used the manual extension tubes from SRB Griturn, it would be very helpful to learn what is the max extension distance they provide. Thanks.</p>

[a_venk]

<p>This is to report back on what worked for those who may later refer to this thread.<br>

(1) Lens reversal was essential to get decent images when I used the MF 28/2.8 and 50/1.8 primes with extension tubes approximating their focal length to get to the magnification ratios (approaching 2:1, ie twice life-size) I needed. Image quality was very good, with the usual caveats about razor-thin DoF and tiny working distances. Stopping down in the f8-f16 range worked well with no visible evidence of diffraction effects.<br>

(2) The SRB Griturn manual extension tubes come in 7, 14 and 28mm lengths. I found them well made and sturdy (anodised metal, good tolerances) as were the reversal rings and coupling rings I also got. Excellent customer service.<br>

(3) The popup flash on both the Nikon D200 and D7000 bodies worked as a CLS commander to trigger slave strobes operating in M mode with reversed lenses or extension tubes (ie., lens not detected by body). Metering with flash was fairly accurate, which makes me suspect that some form of iTTL was being implemented.<br>

Thanks to Jose and Sem in particular for their help.</p>