Reversed Lens Macro Question

[benjyman345]

Hello,

I enjoy doing macro photography and am about to upgrade my DSLR.
I will be purchasing a 105mm Nikon Macro.

It would also be really nice to delve into the greater then 1:1 world and I have been reading up a fair bit about reversed lenses etc...

Some people talk about using two lenses - one attached to the camera normally and one reversed onto the lens. Others talk about using just a 50mm reversed.

My question is using a 105mm macro normally mounted with say a 50mm a good option?

What magnification will this provide?

What are the advantage/disadvantages of each method (1 or 2 lenses)?


Of course the reversed lens is best to be fast/large aperture.
Generally is the wider the lens angle the better? (of course taking into consideration other factors)

Focusing obviously becomes an issue and some mention the use of focusing guide or something like that - is this particularly necessary or are there alternative methods?
Otherwise I guess I'm left with moving the tripod back and forth to focus.

As you can tell I am fairly new to the practice of reversed lens macro and look forward to hearing from people with some more experience.
Sorry for so many questions.

Thanks Heaps.

 

[Overread]

The rough maths that I know for reversing lenses is:

Focal length of the lens on the camera body / focal length of the lens reversed onto it = x:1 (where x is the answer and :1 is its relation to life size)

So a 100mm lens on the camera with a 50mm reversed onto it:
100/50 = 2:1 or twice life size (remember regular macro lenses are 1:1).

Now with a macro lens if you set the lens to focus close the magnification will be greater than 2:1 because the lens itself reduces its focal length as it focuses closer to its minimum focusing distance. However I'm unsure if anything else unique to macro lenses will affect the gained magnification through this method.

Myself in going greater than 1:1 I used the following two methods:

1) Teleconverters - giving a magnification boost equal to their power - so 1.4:1 and 2:1 (1.7:1 as well for nikons 1.7*Teleconverter). Myself I even now often use a 1.4TC attached to a macro lens. The bonus is that it gives me a noticeable boost to magnification; almost no degradation to image quality and I still retain infinity focus for regular shots.

2) Close up lens attachments/filters/diopters - in my case a Raynox DCR 250; these work similar to extension tubes in that they reduce the minimum focusing distance of the lens, remove infinity focusing and increase the magnification. The Raynox ones have a bonus in that they attach with a clip on adaptor; so they can be quickly removed to regain infinity focus as needed.
Note that these work best on longer lenses (ie give more magnification) whilst extension tubes are the opposite and give more magnification on shorter focal length lenses. Note that around 100mm is where most people consider the trade off point - any shorter and you want extension tubes - any longer and you ideally want diopters/close up lens attachments. (note this is a rough ballpack figure and not an exact science).

Combining the two of course gives you even more magnification to play with.


Reversed lenses can give you some really powerful magnifications (50mm lens reversed onto a 70-300mm - at 300mm you're getting 6:1 magnification!), though its an area I've not really done much work in.

 

[benjyman345]

Thanks for the helpful reply!
Do you know the mathematical formula for a single lens reversed?

 

[Overread]

I'm afraid I've no idea of the math for directly reversing a lens onto a camera body. However I will say that its a tricky approach because when done you lose all control over the lens - critically you lose aperture control. I know some older nikon lenses still have the aperture ring and can be manually set to close the aperture blades; however otherwise you'll be needing something like a novaflex adaptor in order to reverse the lens and retain controls (and those are sadly not cheap).

 

[Edsport]

If you're gonna reverse the lens then you don't need to use 2 lenses. With the 105 i suggest extension tubes...

 

[benjyman345]

If you're gonna reverse the lens then you don't need to use 2 lenses. With the 105 i suggest extension tubes...

I'm just interesting to know the difference between a single reversed lens compared to a second lens reversed onto a normally mounted lens? Both methods seem to be used.