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12/08/2007 02:12:12 PM · #1 |
i use the Canon EF 100mm f/2.8 USM Macro for my macro photographs but i'm not getting as close as i would like to or the small insects i shoot clear enough .. i've noticed that the Sigma 150mm f/2.8 EX APO Macro EX DG HSM for Canon gives a much clearer and sharper image but at this time i dont want to buy another lens ..
i'm wondering wot i can do to get better detail .. eg. the hairs on a fly and those amazing segmented eyes ..
wot are extension rings and would they be the way to go ..??
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12/08/2007 02:29:07 PM · #2 |
Both the Sigma and the canon are 1:1 macro lenses; that is to say, at their closest focusing distance they will reproduce on the sensor objects at their actual size. In other words, in a FILM camera if you took the negative you made and laid it on the object, there would be a 1-to-1 correspondence. When you enlarge the image, of course, things are actually larger than life size on the screen or in the print.
Now, the Sigma is a 150mm lens (vs 100mm for the Canon), so it attains its 1:1, life-size image at a greater working distance. But there's no difference in the actual size of the images produced, 1:1 is 1:1 regardless. And the Sigma is NOT a "sharper" lens than the Canon, which is exceptionally sharp.
What you're talking about is getting images that are larger than 1:1 on the sensor, like 2:1 or 3:1, whatever; and yes, extension tubes are the way, or rather one way, to do that. The other way is to take another lens and use coupling rings to reverse mount it (front-to-front) onto your macro lens.
R.
ETA: "what are extension rings/tubes?" ΓΆ€” they are segments that fit between your lens and the camera body, preferably including the necessary connectors to make your metering work (the cheapest ones won't have this), and that, by extending the lens out from the body, increase the magnification of the lens.
Message edited by author 2007-12-08 14:30:49.
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12/08/2007 02:44:33 PM · #3 |
Originally posted by Bear_Music:
What you're talking about is getting images that are larger than 1:1 on the sensor, like 2:1 or 3:1, whatever; and yes, extension tubes are the way, or rather one way, to do that. The other way is to take another lens and use coupling rings to reverse mount it (front-to-front) onto your macro lens.
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There is another other way, which is a teleconverter. It increases your focal length without increasing your minimal focussing distance. The Canon TC can however not be used with the 100/2.8. Third party TC's (Tamron, Kenko, Sigma) can be used with any lense, so this might help.
ETA: note that many of the very detailed macro shots are crops. With a 1:1 macro you should be able to see the segments of a flie's eye at 100%.
Message edited by author 2007-12-08 14:47:40.
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12/08/2007 03:04:40 PM · #4 |
thankyou so much robert and mark .
my camera is a canon 400D ..
i was thinking of selling Canon EF 100mm f/2.8 USM Macro and buying the Sigma 150mm f/2.8 EX APO Macro EX DG HSM for Canon ..
i now understand why i thought the sigma was a better result, because it gets the subject 'closer' not sharper ..
anything i use has to be fairly easy .. the reverse mount is not an option at this time ..
does anyone know the quality that i'd get with extension rings and where i could get them ??.. i would most definitely want the extension rings that have the connectors so that my metering works ..
the camera shops around here are woeful .. they dont even have sensor cleaning equipment which is something else i should ask about ..
i need to clean my sensor .. would i have to order the sensor cleaning pack over the internet and wot is the best to use .. money's no object where this is concerned .. i've googled various sites that give info in how to do it which were very helpful .. i just havent done it yet coz i dont have the equipment etc..
i'll stick in the sensor cleaning sites in case it helps anyone else ..
nuts and bolts of sensor cleaning & the luminous landscape
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12/08/2007 03:13:19 PM · #5 |
Originally posted by roz:
i now understand why i thought the sigma was a better result, because it gets the subject 'closer' not sharper .. |
Hoping to help clarify...
There are two ways of thinking of "closer". One is the physical distance of the subject to the lens. The other is the size of the image projected onto the sensor.
As Bear was saying ... both lenses achieve a 1:1 image size. Meaning they are identical as far as the closeness is concerned if you are thinking about how big the subject will look.
The Sigma, because it is 150mm, will require that you be "further back" (i.e. the working distance) to achieve that 1:1 ratio. In some cases that is a GOOD thing. Because when you're talking macros, you're talking very very short focusing distances.
Which brings me to a question I had. I wonder why you think the 100mm macro isn't "close enough". Are you focusing it at the NEAREST possible distance?
The way you should use a macro lens is like this: Turn OFF the auto focus. Manually set the lens to it's minimum distance. Now move the camera back and forth until the subject is in focus. Take the picture. (preferably using a tripod to stabilize the camera)
You should use this same technique whether you use the 100mm Canon or the 150mm Sigma. The only difference between the two will be that the subject will be "a little bit further away" using the Sigma (again, because it is 150mm). But the image size on the sensor will be the same! (one more difference: the canon is an incredibly sharp lens, there isn't much that beats it)
Message edited by author 2007-12-08 15:13:43.
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12/08/2007 03:14:30 PM · #6 |
I'm not a macro guy, so take this advice as coming from an amateur :-)
There are also things called closeup filters, which allow lenses (usually of the non-macro type) to focus at closer distances. They should allow the 100 macro to focus even closer than it does now, boosting the magnification.
Not quite as elegant as the extension tubes, but likely less expensive.
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12/08/2007 03:22:32 PM · #7 |
Hi Roz,
Was looking for the Copperhill stuff here in Australia and finally came across a site that supported it. I haven't purchased it yet but I called the guy and he was excellent to talk to so I would have no hesitation in purchasing from him.
Here's the link to his site (in Perth) and the Copperhill products.
Copperhill Products - Perth, Australia
Hope that helps. :) |
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12/08/2007 03:32:47 PM · #8 |
One more item to help clarify:
The only time a macro lens achieves its 1:1 magnification, is when you are at the MINIMUM focus distance. Any further away and the magnification will be less than 1:1. So that's why I suggested turning off the auto focus. Manually set the lens to the minimum. Then move the camera in until focus is achieved. That way you can be assured that you have achieved at 1:1 magnification.
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12/08/2007 03:38:56 PM · #9 |
On the subject of extension tubes versus close-up filters:
Extension tubes work by increasing the distance from the lens to the sensor (i.e. you put the tube in between the camera body and the lens). This magnifies the resulting image on the sensor by allowing you to get "even closer" to the subject than what the lens was already capable of doing. There is NO glass in an extension tube. It is hollow. And therefore, it has NO impact on the quality of your lens.
Close-up filters, on the other hand, are a piece of glass that you put in front of the lens (kind of like putting a magnifying glass in front of the lens). They, too, let you move in closer to the subject and therefore achieve a greater than 1:1 magnification. However, because they are made of glass, they will impact the quality of light.
Therefore, if you have the choice between extension tubes and close-up filters and image sharpness is important ... go for the extension tubes. You'll get much sharper images.
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12/08/2007 03:42:59 PM · #10 |
Just to give you an idea what you can get out of the 100mm macro.
 This is the scenario
 This is the shot with the macro (note that I've cropped in a little ways, this is not full size)
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12/08/2007 03:49:59 PM · #11 |
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12/08/2007 03:58:46 PM · #12 |
Originally posted by RamblinR:
Hi Roz,
Was looking for the Copperhill stuff here in Australia and finally came across a site that supported it. I haven't purchased it yet but I called the guy and he was excellent to talk to so I would have no hesitation in purchasing from him.
Here's the link to his site (in Perth) and the Copperhill products.
Copperhill Products - Perth, Australia
Hope that helps. :) |
thanks maria ..
i actually had that site too, but hadnt looked into it .. i'll check it out now .. recommendations are always a very good thing .. :)
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12/08/2007 04:02:48 PM · #13 |
Between those two shots, I think the main differences are:
1) The angle of your shot doesn't have the eyes up front, so the detail you do see in the image, is further away and doesn't appear as impressive.
2) Focus is extremely critical in macro work. As you can see in your shot, the front legs are in focus, but the eyes (which aren't very far away) are not. That's how shallow your Depth of Field is.
Focus is *so* critical, that some people will put bugs into a freezer to cool them down, which makes them sluggish and easier to focus on.
3) If that other shot is straight out of the camera (uncropped), then he had to use extension tubes because that looks to be bigger than 1:1 magnification. He doesn't mention extension tubes, however. So my guess is, he simply cropped in tighter.
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12/08/2007 04:04:52 PM · #14 |
another point i'd like to ask about ..
with the 100mm the closest i can get is .31m ..
if i got the sigma 150mm how close can i get ..
if its further away from the subject then any wobble from the camera would be intensified .. is this correct ..
which would mean i'd be needing a tripod ..
nearly all my macro shots of insects are taken in nature and i'm photographing a subject that is only in one place for a very short time .. a tripod is not an option in this situation ..
would my 100mm be the best for this sort'v thing ??
rather than going for the 150mm or even more ..
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12/08/2007 04:09:22 PM · #15 |
Originally posted by dwterry:
Between those two shots, I think the main differences are:
1) The angle of your shot doesn't have the eyes up front, so the detail you do see in the image, is further away and doesn't appear as impressive.
2) Focus is extremely critical in macro work. As you can see in your shot, the front legs are in focus, but the eyes (which aren't very far away) are not. That's how shallow your Depth of Field is.
Focus is *so* critical, that some people will put bugs into a freezer to cool them down, which makes them sluggish and easier to focus on.
3) If that other shot is straight out of the camera (uncropped), then he had to use extension tubes because that looks to be bigger than 1:1 magnification. He doesn't mention extension tubes, however. So my guess is, he simply cropped in tighter. |
yes i use f2.8 a lot ..
i like the shallow depth of field it gives me, but i'm aware that in this sort of macro that i will be getting focus on an eye for example and not the body .. however, a lot of the time i need the f2.8 because i need a fairly fast shutter speed .. i dont like to go above iso100 because i want as sharp a result as possible ..
i dont know about the freezer .. if the insect revived i'd consider it .. but you've gotta catch him first .. that might be harder than actually taking a photograph in the 'wild' .. !!
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12/08/2007 04:14:12 PM · #16 |
Originally posted by roz:
with the 100mm the closest i can get is .31m ..
if i got the sigma 150mm how close can i get .. |
Slightly further away ... 38cm. So a 1:1 image on the Sigma buys you 7cm of working distance as compared to a 1:1 image on the Canon.
Originally posted by roz:
if its further away from the subject then any wobble from the camera would be intensified .. |
I disagree. They are both at 1:1 magnification. Any bit of wobbling will affect both the same way.
Originally posted by roz:
which would mean i'd be needing a tripod .. |
I wouldn't recommend doing macros without one. In fact, if you're serious about it, you might consider focusing rails.
Originally posted by roz:
nearly all my macro shots of insects are taken in nature and i'm photographing a subject that is only in one place for a very short time .. a tripod is not an option in this situation ..
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In that case, longer is probably better. Because it's hard to get close to insects without scaring them away. So you might consider the Canon 180mm macro. Minimum focus distance (still 1:1 magnification) on it is 48cm (1.6 feet for us North Americans).
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12/08/2007 04:21:08 PM · #17 |
Originally posted by dwterry:
In that case, longer is probably better. Because it's hard to get close to insects without scaring them away. So you might consider the Canon 180mm macro. Minimum focus distance (still 1:1 magnification) on it is 48cm (1.6 feet for us North Americans). |
yes thats the direction it seems i'll be going .. further away from the subject physically but brought closer with the lens .. :)
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12/08/2007 04:23:24 PM · #18 |
Originally posted by roz:
yes i use f2.8 a lot .. |
Aha! That's the problem with getting the necessary detail in focus. At macro distances, f/2.8 is simply *too* shallow. You *must* stop down in order to get more of your subject in focus.
For example, at 31cm away, using 100mm and f/2.8, your Depth of Field is a mere 0.07cm. If you stop down to f/8 (the sweet spot of most lenses) your depth of field is *still* only 0.2cm. I wouldn't go beyond f/11 (we can discuss that too if you like). But here is an Online Depth of Field Calculator.
Originally posted by roz:
a lot of the time i need the f2.8 because i need a fairly fast shutter speed .. i dont like to go above iso100 because i want as sharp a result as possible .. |
Then you might consider upgrading to the Canon 5D. My reason for recommending the 5D is because of the very low noise at high ISOs. That way you could shoot at smaller apertures without having to worry so much about shutter speed.
Originally posted by roz:
i dont know about the freezer .. if the insect revived i'd consider it .. but you've gotta catch him first .. that might be harder than actually taking a photograph in the 'wild' .. !! |
I used to do this as a kid. I'd catch grasshoppers, put them in a jar full of water and freeze them (this would take hours). You'd think they would be dead! I'd take them out and put them on the side walk and watch the sun melt the ice away. Slowly the abdomen would start to move and they would start breathing again. After a long while, they'd simply hop away.
Now, I'm not recommending dunking them in water and freezing them. But chilling them until they become sluggish seems okay (especially since they can obviously survive much worse).
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12/08/2007 04:27:08 PM · #19 |
Originally posted by dwterry:
Now, I'm not recommending dunking them in water and freezing them. But chilling them until they become sluggish seems okay (especially since they can obviously survive much worse). |
it seems that i wont be just buying a lens but a butterfly net as well .. the 5D .. have you got a spare thousand dollars .. !!!
edit .. two thousand dollars !!
just checked out the photographs it can do .. OMG .. some awesome work there .. the indian looks cool .. :)
Message edited by author 2007-12-08 16:30:00.
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12/08/2007 04:30:11 PM · #20 |
Originally posted by roz:
Originally posted by dwterry:
Between those two shots, I think the main differences are:
1) The angle of your shot doesn't have the eyes up front, so the detail you do see in the image, is further away and doesn't appear as impressive.
2) Focus is extremely critical in macro work. As you can see in your shot, the front legs are in focus, but the eyes (which aren't very far away) are not. That's how shallow your Depth of Field is.
Focus is *so* critical, that some people will put bugs into a freezer to cool them down, which makes them sluggish and easier to focus on.
3) If that other shot is straight out of the camera (uncropped), then he had to use extension tubes because that looks to be bigger than 1:1 magnification. He doesn't mention extension tubes, however. So my guess is, he simply cropped in tighter. |
yes i use f2.8 a lot ..
i like the shallow depth of field it gives me, but i'm aware that in this sort of macro that i will be getting focus on an eye for example and not the body .. however, a lot of the time i need the f2.8 because i need a fairly fast shutter speed .. i dont like to go above iso100 because i want as sharp a result as possible ..
i dont know about the freezer .. if the insect revived i'd consider it .. but you've gotta catch him first .. that might be harder than actually taking a photograph in the 'wild' .. !! |
You simply can't use f2.8 at 1:1 and expect any amount of DOF.
If you can't shoot the insects while they're still using a tripod and don't want to increase ISO, your only real option is to add light.
You can use a regular canon flash unit in conjunction with the Off-camera cord and hold the flash above your subject. If you have a flash unit already, that will only cost about $40. You can also get one of the Canon macro flash units, either the MR-14EX ($450) or the MT-24EX ($650) either one of those will let you: Get enough DOF, freeze the insect's motion, let you handhold the camera and let you shoot at 100ISO. There may be 3rd party alternatives as well, but I don't know about any off the top of my head.
Any of those options will be cheaper than a 5D though.
Message edited by author 2007-12-08 16:32:07.
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12/08/2007 04:35:22 PM · #21 |
Here's a lens I'd love to have: Canon MP-E 65mm f/2.8 - it has a WHOPPING 5:1 magnification ratio. No, not 1:5 ... it's 5:1. That means the image on the sensor is FIVE TIMES as big as the subject is in real life!!!
Now here's a question that *I* have wondered about...
Since the closest focusing distance for the Canon 100mm lens is 31cm and it achieves a 1:1 ratio. And the closest focusing distance of this 65mm lens is 24cm (only 7cm shorter but, again, it achieves FIVE-to-one magnification) ... I've wondered if I could get as far back as 5 times the distance (say 155cm) to get a 1:1 magnification with that lens?!? I have no idea ... but it sorta makes sense to me.
This is where I'd have to call Bear in to help out... I think he memorizes this stuff in his sleep. ;-)
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12/08/2007 04:54:36 PM · #22 |
Originally posted by dwterry:
Here's a lens I'd love to have: Canon MP-E 65mm f/2.8 - it has a WHOPPING 5:1 magnification ratio. No, not 1:5 ... it's 5:1. That means the image on the sensor is FIVE TIMES as big as the subject is in real life!!!
Now here's a question that *I* have wondered about...
Since the closest focusing distance for the Canon 100mm lens is 31cm and it achieves a 1:1 ratio. And the closest focusing distance of this 65mm lens is 24cm (only 7cm shorter but, again, it achieves FIVE-to-one magnification) ... I've wondered if I could get as far back as 5 times the distance (say 155cm) to get a 1:1 magnification with that lens?!? I have no idea ... but it sorta makes sense to me.
This is where I'd have to call Bear in to help out... I think he memorizes this stuff in his sleep. ;-) |
Well, I'm not Bear, but I know how this lens works.
It simply moves the lens elements away from the film/sensor like a bellows (which is another option) or extension tubes do.
The closest focusing distance, 24cm, for this lens is from the subject to the sensor plane, but the lens itself will take up a good deal of that 24cm.
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12/08/2007 04:59:33 PM · #23 |
Originally posted by dwterry:
Here's a lens I'd love to have: Canon MP-E 65mm f/2.8 - it has a WHOPPING 5:1 magnification ratio. No, not 1:5 ... it's 5:1. That means the image on the sensor is FIVE TIMES as big as the subject is in real life!!!
Now here's a question that *I* have wondered about...
Since the closest focusing distance for the Canon 100mm lens is 31cm and it achieves a 1:1 ratio. And the closest focusing distance of this 65mm lens is 24cm (only 7cm shorter but, again, it achieves FIVE-to-one magnification) ... I've wondered if I could get as far back as 5 times the distance (say 155cm) to get a 1:1 magnification with that lens?!? I have no idea ... but it sorta makes sense to me.
This is where I'd have to call Bear in to help out... I think he memorizes this stuff in his sleep. ;-) |
The working distance of the lens decreases with increasing magnification, by the time you get to 5X magnification it's about 4cm. |
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12/08/2007 06:14:20 PM · #24 |
Yes, focusing distance is from sensor plane to point of focus. That extreme medical macro, the 65mm, will focus to 24 cm focal plane-to-focal point (sensor-to-subject). At 1:1 the lens will be fully retracted. At magnifications greater than 1:1 the lens is physically moved further from the body, so it's like extension tubes are built in, basically. The entire workings of the lens slides out from its outer tube and gets closer to the subject. But the camera doesn't move, see? The sensor plane is still 24 cm from the subject.
It's a hell of a lens, but VERY expensive.
R.
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12/08/2007 06:16:10 PM · #25 |
Originally posted by Chinarosepetal:
The working distance of the lens decreases with increasing magnification, by the time you get to 5X magnification it's about 4cm. |
If you are calling the distance from the front of the lens to the subject the "working distance", then you are correct. The closest focusing distance remains at 24 cm, however. As far as I cam concerned that's the correct usage of "working distance" btw...
R.
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