Tuesday, 3 November 2009

Reverse Mounting and Reverse Stacking Lenses for Macro Photography

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After this post about the lady bird macro shots, some of you enquired about the technique of lens stacking or reverse stacking. So as promised here`s a post on it.

Simply put lens stacking is just that – stacking one lens in front of another, however  the front lens is reversed. Lens stacking builds on the technique of lens reversal – also called as the poor man`s macro.

The best option for macros are macro lenses (or so they say), however, they are expensive. There are other ways such as extension tubes and close up filters such as the ones I posted about a while back. However, these are not the only ways. One can get close to the subject and get more magnification, simply by reversing an existing lens onto your camera. If you directly look down your lens the reverse way you can see what I`m talking about. Put the wrong way around, your lens turns into a magnifying glass!

It is possible to hand hold the reversed lens but you`ll see instantly how difficult it is to do that and focus at the same time…an alternative is to get a reverse mount adapter for your camera. DSC08837

These can be bought cheaply off ebay or your local camera shop. These are basically rings with the camera mount on one side and a thread which screws into the front of your camera on the other side. So basically, you can screw the latter into your lens and mount it reversed onto your camera.

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If all you can see is black, then you need to open up the lens aperture to its widest to allow in more light. This can be done by moving the small lever on the back of most lenses. In manual focus lenses with an aperture dial, you can do this simply by turning the dial to its widest (lowest number).

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Those of you who have tried it will see the improvement. You are now able to get much closer to your subject and hence get much more magnification.   However there are several disadvantages as you`ll soon notice:

a) you lose auto metering.

b) you lose auto focus (which may not be much of a problem as manual focus is the mode of choice in macro photography)

c) some cameras (like mine) will not detect a lens as being present at all and thus you will have to go into a full manual mode.

d) since the depth of focus is very narrow, and the distance from the object is very little, most of us would be apprehensive exposing the interior of an expensive lens and risk getting it scratched.

e) some of us begin to wonder if this is all worth it..even the magnification attained is not that great (like I thought it would be)

 

so what is the alternative? I’ve tried lens reversal and wasn’t very impressed, I wanted to get more out of it. Then I came across the technique of reverse stacking lenses. For this you will need two lenses

- one lens which you mount on the front of your camera as normal – this can be anything from a 50mm to a 200mm lens. Zoom lenses will do too. I use my Sony 50mm F1.4 lens. Often in macro photography, you will need that extra bit of light and the wider the aperture of your lens the better.

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-the second lens is the lens that you reverse and stack back to front on the first lens. This lens is ideally 50mm or less and preferably needs to be of a wide aperture (f1.4/f1.7/f1.8/f2.8 or thereabouts – again the wider the better).

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So yes it does require two lenses but the great part is that the second lens can be an old manual focus lens of a completely different make, and you can get these really cheaply on ebay. Infact, old manual focus lenses with an aperture dial is more preferable. I was able to get this f1.4 58mm Minolta for £30. What you need to watch out for is whether the thread size of the filter on both the lenses are the same size. (Although you may get stacking adapters that may be able to marry lenses of different thread sizes, they are hard to come by.)

Once you have both your lenses you need to reverse mount it, and this is where a reverse stacking adapter comes in handy.

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Once again, you could buy them online, quite cheap. These are basically rings with male threads on both sides, which screw onto the front of both lenses allowing you to mount one lens front to back on the other.

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Once mounted mak
e sure your aperture on the front lens is set to its widest
and the focus dial is set to infinity. Once these are set you dont need to change it afterwards. They remain the same.  You can make any required adjustments on the main lens or on the camera itself.

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You will find that you can get amazingly close to you subject, just inches away! the magnification is whopping and it depends on your lens combination. Basically it is the focal length of the 1st lens (longer one on your camera) divided by the 2nd lens (shorter one)- the one that you reverse mounted. So if you reverse mounted a 50mm lens onto a 200mm lens you would get 4x macro! that is four times life size! (of course don’t forget to add your sensor crop factor to that!!).

The advantage of this technique, apart from the awesome magnification you get is that autofocus and auto metering is retained. It however shares some of the disadvantages of lens reversal such as a limited depth of focus etc but that is part of what gives the great pictures. The narrow depth of focus means that one has to be very steady while taking the pics and also a tripod might be a good idea. I get around this by clicking a vast number of pictures while trying to be as steady as I can. Atleast one or two out of numerous ones are bound to be good.

However, looking through the viewfinder of a dSLR at something that is at ground level is not ideal. I find myself having to crouch really low or lie in the grass to get the right angle. Unfortunately my camera doesnt have live view or a twistable/ extendable monitor…..however, my point and shoot Sony DSC H9 bridge camera has both of these features.

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I thus use this camera for my macro photography.  Another advantage of using this camera is that I can adjust the zoom as required…at around 3.5x i can eliminate any vignetting (the darkness around the edges)..and the rest of the zoom is free to adjust as my composition requires. I also find that at higher zooms there is a bit more working distance between the lens and the camera – something that i found wanting with the dSLR. Finally, with my point and shoot, I can also take movies. Here is a movie starting from the basic to the most zoomed in while I was trying to get some pictures of a spider.

 

 

…and here are some sample pictures I obtained with the lens reversal technique:

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Please leave a comment on what you liked or disliked about this post. Any thoughts on technique or improvements are welcome.