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Forum: Lens Clubs
05-28-2012, 08:22 AM
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I sent the 150 back and am now the proud owner of the 250! :cool:
I've done some tests with my tamron 90mm and here are the results along with those of the DCR-150.
Infinity focus:
DCR-150
Working distance 200mm
Width 56mm (0.42x or 1:2.4)
DCR-250
Working distance 120mm
Width 33mm (0.72x or 1:1.4)
Closest focus:
DCR-150
Working distance 55mm
Width 16mm (1.48x or 1.5:1)
DCR-250
Working distance 45mm
Width 13mm (1.82x or 1.8:1)
16mm width (1.48x closest with DCR-150)
DRC-150
Working distance 55mm
DRC-250
Working distance 57mm
1:1 focus
No diopter
Working distance of 94mm (0.96ft on focus dial - closest focus)
DCR-150
Working distance of 80mm (1.1ft on focus dial)
DCR-250
Working distance of 83mm (1.5ft on focus dial)
Here are three pencil shots at closest focus:
Pencil at closest focus without any diopter
Pencil at closest focus with DCR-150
Pencil at closest focus with DCR-250
Incredible results - The DRC-250 actually has better working distances than the DCR-150 for 1:1 or greater magnification!!!!!
I'm really glad I sent the 150 back :D
A really handy thing I've just noticed is that turning the focus limiter on on the lense with the DCR-250 attached ensures that all shots will be over 1:1...very nice - so I'll know that if I need to get further away I should remove the raynox....
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Forum: Lens Clubs
05-23-2012, 06:08 AM
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Some uncropped pics with the Tamron 90mm and the 150:
Sheild Bug
Ladybird
Blue Greenfly
Pollen Beetles
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Forum: Lens Clubs
05-23-2012, 04:38 AM
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I've finally managed to get hold of the 150 and have done some careful measurements:
My sensor is 23.6mm wide
Infinity focus with 150 attached
This was 200mm from the very end of the Raynox. (lense probably recessed about 8mm) to give 23.6/56=0.42x magnification (about 1:2.4)
Closest focus with 150 attached
This was 55mm from the end of the Raynox - gives 23.6/16=1.48x magnification (about 1.5:1)
So the working distance range is 55mm - 200mm
with magnifications of 1.5:1 - 1:2.4
So what about a comparison of working distances at the same magification?
Closest focus of Tamron 90mm without 150
This was 94mm from the end of the lense - gives magnification of 23.6/23=1.03x (1.03:1)
Setting up the lense with the raynox attached so that the exact same area is in the frame: This turned out to be where the lense markings read exactly 1.1ft
lense set to 1.1ft with 150 attached
The distance from the end of the Raynox to the subject was 80mm at this magnification
So you lose about 94mm - 80mm = 1.4cm of working space when you attach the raynox at this magnification.
Looking at the first image, the max working distance with the raynox attached is 200mm which fits in 56mm of ruler
Tamron 90mm at 56mm width without 150 attached
The working distance here was 225mm
so 225mm - 200mm = 2.5cm lost working distance.
and some pictures comparing the lense at closest focus with and without the 150 - so you can really see the difference.
With
:
Without
In Summary:
The working distance range is 55mm - 200mm with magnifications of 1.5x - 0.42x (1.5:1 - 1:2.4)
At 1:1 magnification the 150 requires you to be 1.5 cm closer to the subject than you have to be without the 150.
At the other end (0.42x magnification) you need to be 2.5cm closer.
Conclusion:
First of all, the quality is great and there is no sign of vignetting at any magnification with this lense.
The increase in magnification is not really that much with the Tamron 90mm - from 1x to 1.5x - with a hit of 1.5cm working distance at the 1x end. From my pencil shots I realize that I really want to get closer than this...
So I'll be sending it back and getting a 250..(it's only £5 more at the moment). Hopefully the working distance won't be too extreme...
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Forum: Lens Clubs
05-14-2012, 02:18 PM
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Oh dear, I think I really need to try these out... or have someone who has experience with the raynox and the tamron 90mm to tell me what they are like together.. These equations really aren't getting me far.
I look forward to reading about what's going on, once you have deciphered your mumbo-jumbo ;)
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Forum: Lens Clubs
05-14-2012, 02:19 AM
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Doing some measurements - subject to lense at various magnifications - and trusting the magnification dial on my lense, it seems that 1:1 magnification with a raynox attached, should be achieved when the lense reads just under 1:1.8 for the 150 and just under 1:2 for the 250 (by using the second formula from above).
For these magnifications, I get working distances (measured with a ruler) of about 230mm and 250mm (these are measurements without any diopter or anything).
Then, using the first equation, 1:1 magnification should be achieved with about 109mm working distance for the 150 and 83mm working distance for the 250.
So, incredibly, the raynox 150 should actually improve working distance at 1:1 magnification by just under 2cm!!!!!!!!!!!!!
This, I'm sure, is due to the 55mm recess of the lense. (the diopter reduces working distance by 3cm and then then the lense is moved forward by 5cm)
The 250 isnt bad either losing only about 1cm of working distance.
This is all of course specific to my particular lense (tamron 90mm macro).
I'd love to hear what people's real experiences of this lense is.. is this what you are actually seeing?
If it is correct then the 150 is a no brainer accessory for this lense, even if you are not interested in getting closer than 1:1, and I'll be getting a 250 for sure! :D
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Forum: Lens Clubs
05-11-2012, 06:51 AM
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Ahhh, thanks Dave - a very imformative post...
From all that, I have derived the following for my lense (all measurements from the diopter):
150 has a working distance range of 85mm-208mm and magnifications of 1.7:1 - 1:2.3
250 has a working distance range of 67mm-125mm and magnifications of 2.2:1 - 1:1.4
The 150 doesn't seem to have much of a working distance hit (a mere 5mm for a 0.7 increase in magnification) - very nice.
Even the 250 isnt too bad (23mm for 1.2 increase in magnification)
I expected it to be much worse than this...
I also derived these handy equations from the many used...
WD = (f' * d) / (f' + d)
M = m + (md)/f'
where
WD = working distance when diopter attached
d = working distance without diopter (at the same focus setting)
f' = focal length of diopter ( = 1000/D)
M = magnification with diopter
m = magnification without diopter (at the same focus setting)
note: in equation 2, when at infinity focus, then m=0 and md=Focal length of lense.
Unfortunately, setting M = 1 (in an attempt to find the working distance at 1:1 with the diopters attached) and substituting into the first equation yields
WD = (1-m) * f'
which is a nice looking equation but not very helpful if you don't already know where the focus ring has to be for a 1:1 magnification - and of course without actually trying it out how could you know?.
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Forum: Lens Clubs
05-10-2012, 08:39 AM
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Ahhhhh... It seems to me that the focal length of the diopter (125mm for the 250 and 208mm for the 150) is the working distance from the lense and NOT from the diopter. This explains a lot of my confusion!
So moving the diopter does not change the position of focus. (which is probably what you were trying to tell me earlier Dave! :D )
so...my revised (and final?) working distances (from the end of the lense) should be
150 has a working distance range of 35mm-158mm and magnifications of 1:2.3 - 1.7:1
250 has a working distance range of 17mm-75mm and magnifications of 1:1.4 - 2.2:1
This is for the tamron 90mm macro...
with no filter the closest focus is 90mm at 1:1 magnification.
Seeing as Im only really interested in what these diopters can do above 1:1 with this lense, it would be useful to be able to calculate what the working distance would be at 1:1 for each. Unfortunately I haven't been able to calculate this so far...I must be missing something... hmmmm...
Edit: See post #399 for the correct figures
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Forum: Lens Clubs
05-10-2012, 01:57 AM
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When doing the Maths, it gives me the distance from the sensor to the subject. This is 230mm for the Raynox 150 and 212mm for the Raynox 250.
At this close focus, my lense is 145mm from the sensor and the raynox is another 50 mm in front of that.
Surely that means that I must do 230-145-50 = 35mm from the raynox 150 lense
and 212-145-50 = 17mm for the raynox 250 lense?
This makes more sense when comparing it to my lense without the raynox too...
if so then the 150 has a working distance range of 35mm-208mm
and the 250 has a working distance range of 17mm-125mm
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Forum: Lens Clubs
05-10-2012, 01:33 AM
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Hmmm I think that there must be something wrong with my maths.
The closest focussing distance on my lense without any extra glass is 290mm (from the sensor). I calculated that when focussed at this distance the lense is extended by an extra 55mm making it 145mm from sensor to lense. Then 290-145 gives 145mm working distance from the lense which means 145-50=90mm from the end of the lense.
so without the raynox, my lense gives 1:1 magnification at 90mm distance from the end of the lense. (this agrees exactly with measurements with a ruler)
with the raynox 150 I calculated that I should get 1.7:1 magnification at 140mm from the end of the lense....
Arggghhhh that doesn't make sense.....The raynox improves working distance??? :confused:
EDIT:
Ahhh I think I see the problem: In my original calculation I forgot to subtract the extra extension from being focussed in close. That would change my 140mm to 85mm.
This seems more reasonable but it is still pretty close to the 90mm without extra glass.... Surely the comprimise must be more than this??? (if not then I'll buy one right now!!)
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Forum: Lens Clubs
05-10-2012, 01:09 AM
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Oh, right, that is interesting, so the results that I found for working distance are from the outermost glass? ie the raynox? That would improve things somewhat! :)
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Forum: Lens Clubs
05-09-2012, 09:11 AM
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Hi, I have read this entire thread through...Phew, it's long....
I have a tamron 90mm macro lense and was wondering what magnifications and working distances people were getting with their 100mm macros with either the 150 or 250 raynox lenses, and also whether there is any vignetting at all at various focus settings.
Using the equations pointed to at a couple of points in this thread I have come up with some theoretical limits, I was wondering whether they are about right or not
Using the 150
Infinity focus: 1:2.3 at about 208mm working distance
Closest focus: 1.7:1 at about 140mm working distance
Using the 250
Infinity focus 1:1.4 at about 125mm working distance
Closest focus 2.16:1 at about 67mm working distance
Maybe my maths is a bit off, but do peoples experience of a lense of this type and size approximately match?
Is it also possible to focus at all magnifications in-between without vignetting?
Thanks for any replies, I'm trying to decide whether the 150 or 250 would be best with my lense.
Edit: Also with my particular lense the glass is recessed by about 50mm, so the distances from the end of the lense to the subject should be about another 50mm less than the above!!! That leaves a mere 17mm for the 250 max magnification!!!!!!!!!!!!
Edit: See post #399 for the correct figures
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