Bronica ETRS extension tube help

Hi there

i was wondering if anyone had much experience with the bronica ETR extension tubes at all. I am looking for a way to take macro shots of plants close up and wonder if one of the extension tubes would do the job. I have a 75mm and a 150mm lens and I see theres an E-14 extension and a couple of others. I have no idea which would be best but which one would get me closest and which of my lenses would be best, the 75mm? also does anyone have any test photos with and without using one? Any help much appreciated, I don't really understand which one of the tubes would get me closest, I've seen a chart but don't understand it. Any help much appreciated!

. . . i was wondering if anyone had much experience with the bronica ETR extension tubes at all. I am looking for a way to take macro shots of plants close up and wonder if one of the extension tubes would do the job. I have a 75mm and a 150mm lens and I see theres an E-14 extension and a couple of others. I have no idea which would be best but which one would get me closest and which of my lenses would be best, the 75mm? also does anyone have any test photos with and without using one? Any help much appreciated, I don't really understand which one of the tubes would get me closest, I've seen a chart but don't understand it. Any help much appreciated!

Bronica’s Technical Sheet lists three Extension Tubes for the ETR Series: E-14; E-28 and E-42.

If you have the 75/2.8 and 150/4 lenses, then:

1. The longer the Tube you use, the more magnification is possible, with any one lens you choose.

2. The longer the Lens, the greater the Working Distance, with any one Tube you choose.

3. Working Distance, is the distance between the Front of the Lens and the Subject.

4. The longer the Tube, the more exposure compensation is required.

***

Using the E-42 Tube and the 75/2.8 lens will provide the most magnification possible of all the combinations of your two lenses and the three Extension Tubes. The Magnification range for this combination being: 0.54x magnification when the lens is at the infinity position to 0.72x magnification when the lens is fully extended. You will need to adjust the exposure by about 1 Stop at the least magnification and to about 1½ Stops at the most magnification. The Working Distance Range being: 176mm to 140mm.

***

Typically, when a seasoned Macro Photographer discusses “Macro-photography” they will expect a 1.0x Magnification or greater and anything less would be termed “Close Up”. I mention this because you might not want “macro” shots of Flowers, you might only want “Close Up”.

A 1.0x Magnification (sometimes written as the Magnification Ratio “1:1”) means that the image on the film or sensor is exactly the same size as the object. So, you need to think through what you actually want – ‘how close you do want to get to the plant?’ In your situation, your Neg Size being 60mm x 45mm, if your plant is 200mm wide, then using the E-42 and the 75mm lens might not be what you want, it might be too much magnification and not show enough of the plant's structure.

Extension Tubes are one way of making very good to excellent Close Up and (with enough extension) Marco Shots – but in most situations the Extension Tubes are only one of the many tools necessary. For Plants, you’ll probably need a good Tripod and Head and/or a Flash Unit set up specifically for this type of work. If you don’t use Flash, then you will need a stable (still) Flower in a no-wind environment.

***

One of the value ads for Extension Tubes is they can be piggybacked. Photographers who use Tubes typically buy the set. You’ll note the Bronica Tubes E-14 and E-28 could be connected together and effectively that would make an equivalent E-42 Tube.

***

What’s your budget?

WW

As above replies suggest, it somewhat depends on your goal.

Do you want to do serious macro in the 1:4 to 1:1 range (single bloom or leaf fills frame)? Then you'd need all the tubes to use in various combinations with both lenses. Focus range will be discontinuous, with gaps in the distance ranges and magnifications possible with a given lens/tubes combo: pre-visualizing the shot is helpful. If using one of the TTL meter prisms, exposure will be compensated automatically, otherwise you will need to make various calculations depending on the lens/tube/helical combo.

Or were you thinking more along the lines of "closeup" than "macro"? Closeup would fill the frame with two or three blooms, and/or show more of the plant and environment, but perhaps not get you close enough for details to fill the frame. For this type of shooting, you generally want to match the tube size to the lens' own helical extension (so the tube gives you maximum additional close focus ability without overlapping the range the lens can do on its own). Such a tube/lens match means you seamlessly go from the lens minimum focus on its own, directly into the range added by the tube when you attach it, with no significant gaps in distance/magnification range. If this is how you'd like to work, use the 14mm on the 75 lens and 28mm on the 150 lens. As above, a TTL meter prism would simplify exposure compensation.

Often one needs some physical working distance between the lens and subject to allow for tripod intrusion, camera shadow reduction, and space for reflectors or flash units. The longer the lens, the longer the working distance to fill the frame at the same size. When you need breathing room, use the 150, when that doesn't matter as much as maximum magnification, use the 75. While frowned upon by some as amateur junk, it is useful to also keep a set of three "closeup filters" in your kit (0.5, 1.0, 2.0). These can be combined quickly and easily with extension tubes for extreme detail shots, although you may be almost touching the flower and the filters can add some optical aberrations (usually not an issue in flower work).

Seriously, thanks William and Orsetto for your help here, such amazingly detailed answers that for me is so , thank you. oK so i would love to try and take a photo like this one I found or similar. What would be the best combo in your opinions so I can look for one online. I want to capture as much detail as possible. I feel like this would be such a great place to start. I have a tripod and it'll be indoor plants so hopefully we can keep them still enough during that.

[LINK]

Moderator Note: Image Removed, please refer to Terms of Use and User Guidelines - you may only publish Images that you have made yourself.

I don't own a Bronica ETR, but just did a quick check with my Hasselblad. The Hassy is 6x6 format so not directly comparable to ETR, but my grid focus screen makes it easy to see a 645 crop. Hadn't used my tubes for awhile so was a bit surprised how close I could get: my remarks above about the 14mm tube not getting quite so close were in error (I must have been thinking of the shorter 10mm tube I also have for my 'blad).

Using the Hasselblad 16mm extension tube and my 80mm lens, it is definitely possible to take the shot above assuming 645 framing and the rose size is roughly 5" from top to bottom as posed. Front of the lens is about a foot away from the flower. It is also possible to do this shot with the 16mm tube and my 150mm lens: in that case working distance is closer to two feet, but depth of field is razor thin so stopping down and longer exposure would be necessary. Outdoors with a breeze would be tricky, indoors much easier. There is enough adjustment range via the focus ring to get a little closer or further away, to match this composition with a smaller or larger flower.

The Bronica 14mm tube and 75mm lens are of course slightly shorter than my Hasselblad 16mm tube and 80mm lens, but the roughly 1:8 ability to shoot this composition should be nearly the same. The Bronica 28mm or 42mm tubes would get you even closer- near-macro 1:4 to 1:2 detail range.

It is relatively easy to predict/calculate the effect of adding an extension tube. The length of the tube divided by the focal length of the lens gives the image magnification on film/sensor.

A 14 mm tube used on 75 mm lens (set to the infinty mark) produces a magnification of 0.1866 x. A subject of, say, 1 cm in real life will be rendered 1 x 0.1866 cm on film.

Or, inversely, the focal length divided by the length of the tube gives the scale, in this instance 1:5.3571.

So multiply the nominal 6 cm width of your film frame with 5.3571, and that's the field of view you get: 32.14 cm (much too precise), nominal.

You can add the extension built into the focusing mount. ETRS lenses probably all are unit focusing lenses, so the difference in length of the lens between the lens set to infinity and the lens set to its close focus limit will be the amount of extension the lens can provide in addition to the 14 mm (in this instance) of the tube. Add that length to the length of the tube and use the result in the calculations above.

Not knowing the extension the 75 mm's mount comes with, so assuming the lens set to infinity, adding a 28 mm tube will yield a scale of 1:2.678 (nominal field of view 16 cm) i.e. magnification of 0.373x, while adding a 48 mm tube results in 1:1.563 or 0.64x.

The Bronica Data Sheets in my library confirm the above suggestions and the information.

As mentioned and alluded to by Eddie (orsetto) and Q.G de Bakker, precise measurements apropos magnification factor and field of view are not really necessary in the real world of Photography, you’ve got wiggle room and provided you have a Tube and Lens to get you in the ballpark of FoV and at a suitable Working Distance, you’ll do OK – again mentioning that: Lighting; controlling the environment (wind, meaning Subject Movement): and stable camera (Tripod and Head) are the main other factors that you need to consider.

However, the detailed technical information above should be of benefit to you in your journey.

My bottom line suggestion would be to get an E-14 and E-28. Those two Tubes combined with your two Lenses will provide a combination of six (6) different Working Distances and Magnifications and that range of options seems to me to be a good fit for what you want to do. Buying those two Tubes was exactly what I alluded to in my previous.

If you can only acquire one Tube, then I think the E-14 should be your first purchase.

WW

Good.

Let's know what eventuates. Many folk don't.

The best part of offering advice and help: is knowing the results.

WW

Hey all ok as promised heres my first photo using the first extension tube to arrive, its the largest one so the E-42. Its looking like it'll be a great tool, photo can improve but I'm very happy.

I'm very happy.

That's fantastic.

That's fantastic.

Thanks William, this sites crazy helpful for me getting into all of this. I post all the time I feel haha!

this sites crazy helpful for me getting into all of this.

hahaha. Very good, nice to read. Stay crazy happy with all this Photography stuff.