Can you guess the flower?

[Cyclops]

inspired by a post by NU here's a tiny flower that I found while on my travels today.
I just took 3 pics of it, one at lifesize, one at 2X and one at about 3.5X
I shalll post the latter first and see how you get on with it!

Canon 10D
100mm macro lens + Hanimex 28mm lens reversed(28mm lens stopped down to f22, 100mm macro lens at f3.5-lit by my mobile phone with a long exposure,hence the slightly soft look)

[NikonUser]

A conifer.
Female flower of Taxus??

[Cyclops]

Ohhhh and I thought this would be hard!
Heres another part of the stem at 2X
(100mm + Pentax 50mm lens reversed)
Edit-correct image:


and heres the whole thing at lifesize;

[Franz Neidl]

Maybe Taxus baccata.

kind regards
Franz

[Cyclops]

Maybe Taxus baccata.

kind regards
Franz

Yep,thats the one!
Amazing the difference in field of view between lifesize and 2x!

[rjlittlefield]

Amazing the difference in field of view between lifesize and 2x!

Indeed. So amazing it indicates that one or the other is wrong. The ratio of field width should be the same as the ratio of magnifications. But by my measurements, the ratio between your 2nd and 3rd shots is 3.47:1, not 2:1.

Could you perhaps have accidentally slipped in another 3.5X shot instead of a 2X? If not, then it would be interesting to stick a mm scale in front of your camera, the next time you have these lens combos set up. Perhaps the actual magnifications are not what the simple calculations suggest.

--Rik

[Cyclops]

Could you perhaps have accidentally slipped in another 3.5X shot instead of a 2X? If not, then it would be interesting to stick a mm scale in front of your camera, the next time you have these lens combos set up. Perhaps the actual magnifications are not what the simple calculations suggest.

--Rik

Hmmm you could be right there! I still have the shots on the memory card,must check. Actualy i might have a play with a ruler,see what field of view I get at each supposed magnification.(The 100mm macro lens becomes a 160 mm on the Canon,might that not have something to do with it? My setup is to reverse either a 50 or a 28mm lens. That is to say an 80mm or a 44mm[rough conversion guess there])

[rjlittlefield]

The 100mm macro lens becomes a 160 mm on the Canon,might that not have something to do with it?

Sorry, but the 100 mm lens does not "become a 160 mm on the Canon". It remains a 100 mm lens. All that happens is that the Canon grabs a smaller portion of the image circle. When focused on a distant landscape, indeed the 100mm on your 10D does act just the same as a 160mm on full-frame 35mm film. When focused at any shorter distance, the two setups will not behave the same. But I digress...

There is another likely culprit that can mess up the simple calculation of magnification = FLrear/FLfront. That calculation is valid only when the rear lens is focused at infinity. If the rear lens is focused closer -- say if you set the rear lens at 1:1 -- then the magnification will be somewhat higher.

Calculating how much higher is at best a challenging problem.

'Tis far better to just measure it.

Take pictures of a mm rule, read off how many mm of field width at the subject, and calculate magnification = 22.7/FieldWidth. (22.7 is the width of your 10D's sensor, in mm.)

For example if you measure a field width of 7.5 mm, then you're looking at magnification = 22.7/7.5 = 3.

--Rik

[Cyclops]

The 100mm macro lens becomes a 160 mm on the Canon,might that not have something to do with it?

Sorry, but the 100 mm lens does not "become a 160 mm on the Canon". It remains a 100 mm lens. All that happens is that the Canon grabs a smaller portion of the image circle. When focused on a distant landscape, indeed the 100mm on your 10D does act just the same as a 160mm on full-frame 35mm film. When focused at any shorter distance, the two setups will not behave the same. But I digress...

There is another likely culprit that can mess up the simple calculation of magnification = FLrear/FLfront.

'Tis far better to just measure it.

--Rik

Now hang on. Surely the 'sensor crop factor' is a signifiant element when choosing a lens. After all every source quotes the 35mm equivalent for each lens. Which is why the new line of wide zoom lenses start at about 10 mm(16mm equivalent). I know this because I had a devil of a job finding a lens wide enough that i could afford. In the end I went for an older 19-35mm. This becomes around a 30-50 when used on the 10D but when I put it on the film camera it becomes a lot wider!

[rjlittlefield]

Surely the 'sensor crop factor' is a signifiant element when choosing a lens. After all every source quotes the 35mm equivalent for each lens.

Yes it is, and yes they do. I never said otherwise.

At far focus, "35 mm equivalent" is a simple and effective way to think about the relationship between lens length and sensor size. It doesn't produce exact results --- for example the DOF's are different at same f-number --- but for angle of view it works great. Simple and works great -- that's why it's popular.

But for close focusing & small subjects, life gets more complicated and the "35 mm equivalent" concept can lead you astray.

I'm not a purist about terminology. If one could get correct results by simply substituting "35 mm equivalent" everywhere a focal length is needed, then I wouldn't spend time discussing this. But it doesn't work that way. Sometimes one has to think about what a lens physically is, and not try to get along by thinking about an "equivalent" lens on a different camera.

--Rik

[Cyclops]

so basically, and an eway way of looking at it, is using the 35mm equivalent is fone for landscapes, but it breaks down at the close up and macro range.
Thanks Rik, this has been a great help!

[Cyclops]

i just found the correct image and edited my post above-I obviously uploaded the wrong one at the time!

[Ken Ramos]

Um, um, um, facts and figures, ya'all lost this old country boy but that last photo is pretty cool!

[Cyclops]

thanks Ken!