Need advice about tube lens for infinite objectives

[D.d.K]

Hello guys,

I need your help!

I’m shooting macro (1:1 and 2:1 with extension tubes + raynox) for a while now.
I want to improve myself and that’s why I ordered a 4x and 10x infinite objective from wemacro. Already own a wemacro stack rail.

Because my girlfriend already has a tamron 16-300 i thought it wouldn’t be necessary to buy a tube lens.
Althought, after I tried some shots, i’m getting vignetting, even at 300 just a tiny bit, and my shots aren’t sharp. A bit blurry.
The aperture blades wide open on this lens is f6.3

I’ve read about the raynox 150 as a tube lens.
Would this be the best option?
What do I need exactly to create a tube lens on the right length/distance?

I’m using a canon 760d aps-c.



Thanks in advance

[D.d.K]

The shot was taken with the 10x objective, lens at 300mm, f6.3, 1 sec shutterspeed, 2 led bulbs, foam cup as diffuser, 10um


Also need to make a sturdy rig, there was a lot of movement during the shoot.

[/img]

[Deanimator]

Regarding movement/vibration, if you don't want to go nuts like me and build something appropriate to the Maginot line, since you already have the Wemacro rail (as do I), you might want to think about the Wemacro base.

[rjlittlefield]

I’ve read about the raynox 150 as a tube lens.
Would this be the best option?
What do I need exactly to create a tube lens on the right length/distance?

Raynox 150 makes an excellent tube lens.

See http://www.photomacrography.net/forum/v ... hp?t=35350 for some discussion about how to make a tube assembly out of parts from Amazon. Note that the thread extends across three pages, with useful comments throughout.

Optically, it's just a matter of getting enough non-glaring tube behind the Raynox to make the Raynox, by itself, form a focused image when looking at a distant object. Mechanically, you'll need a string of several parts to get from Canon bayonet to the Raynox's screw threads, and from there to the objective's threads.

I see that WeMacro now sells a Raynox tube lens assembly, https://www.wemacro.com/?product=raynox ... e-lens-pro . If you already have the Raynox, you might ask if they'd make you a special deal on the tube parts.

--Rik

[D.d.K]

I see that WeMacro now sells a Raynox tube lens assembly, https://www.wemacro.com/?product=raynox ... e-lens-pro . If you already have the Raynox, you might ask if they'd make you a special deal on the tube parts.

--Rik

Yeah, i saw it too. Just been uploaded yesterday.
Althought, they’re talking about distance from sensor to raynox should be around 204mm.

But I also have read a distance of 208,33mm

[rjlittlefield]

Althought, they’re talking about distance from sensor to raynox should be around 204mm.

But I also have read a distance of 208,33mm

The number 208.33 comes from reading too much into the official specification for the lens. The Raynox DCR-150 is specified as a "4.8 diopter" lens, which implies a focal length of 1000/4.8 = 208.33 mm. Even if that is exactly the right focal length (not likely), the measurement would be from the sensor to a special location called the "principal plane", which for the Raynox is probably located someplace inside the lens housing. (Principal planes can be outside the lens housing for some types of lenses.) Reversing the lens changes the location of the principal plane, so in terms of the extension required to get infinity focus, that's different for normal versus reversed.

Nominally the best extension will be whatever makes the Raynox focus by itself on a far distant object like the moon or a landscape horizon. But even that can be reading too much into a specification, since it depends on the idea that infinity objectives are designed to be used with a tube lens that is focused at infinity. In careful tests, it often turns out that the best image quality is achieved using an extension that is somewhat different from infinity focus, due to interaction between aberrations that are not included in the specifications.

For most people, all this is probably worrying too much about minutia. Focusing the Raynox at infinity, or copying a design from somebody else who focused their Raynox at infinity, will produce quite a good image.

--Rik

[Yawns]

I presume you're just beginnng ...
If I were in your place, I would get a simple 55-250 zoom (usable from 180>> )
Cheap and simple to use..., just needs an adapter for the lens mouth..

eBay link to above lens.

You just have cheap consumer objectives .. in your place, at the moment, I would not stress about the "best" tube lens...

And you will have so many other things to learn the ropes and master... light, diffuser, specimen holder etc... learn the ropes with something simple and with time you start to replace components for better parts up as you go getting more skilled and getting better results.
The zoom will give you a certain degree of flexibility .. 3,6-5x.. 9-12x.. the Raynox is rigid.
I don't know... it's difficiult to advise this or that.. the options are so many, we are all so different in character and goals , budgets etc...
That's my 50 cents.

(AdminCS edit formatting)

[D.d.K]

I presume you're just beginnng ...
If I were in your place, I would get a simple 55-250 zoom (usable from 180>> )
Cheap and simple to use..., just needs an adapter for the lens mouth..

Can this lens be set at infinity focus? Can’t find it.

I don’t want the best of the best tube lens, if there is a “best”.
but don’t want to spend/waste a lot of money buying a lot of things to try out..
Just starting with a good tube lens i can use for a long time that can make decent images.


Another question: is vignetting a common issue using a microscope in combinition with bellows, zoom lens, raynox tube lens ?

[Chris S.]

I see that WeMacro now sells a Raynox tube lens assembly, https://www.wemacro.com/?product=raynox ... e-lens-pro.

Impressive—turn-key, Arca-standard, and low-priced. No need for trial and error; no sending off this way and that for various bits. No need to read tons of forum posts and scratch one’s head.

It would appear that in this product, WeMacro has neatly distilled threads at our forum spanning several years and quite a few members' contributions. It’s great when the fundamental research so well-conducted by our community is applied this way by entrepreneurs.

If I were in your place, I would get a simple 55-250 zoom (usable from 180>>)
Cheap and simple to use..., just needs an adapter for the lens mouth.

. . .in your place, at the moment, I would not stress about the "best" tube lens...

While the zoom has its merits, I like Rik’s suggestion that D.d.K. look at the new WeMacro offering—particularly if they will sell it without the Raynox optic that he already has, and reduce the price accordingly. One reason is because of this element of D.d.K.’s needs:

Also need to make a sturdy rig, there was a lot of movement during the shoot.

For stability on an infinity-objective-based macro rig, it’s hard to beat mounting the converging lens assembly solidly on an Arca-standard plate, and hanging the lens on one end and the objective on the other. This can place the center of gravity in the middle of the assembly. It also provides easy ways of adding more Arca-standard clamps and braces in the future, if additional rigidity is needed. Comparatively, the zoom lens is a rear-mounted, front-weighted dead end.

I concur with you about not stressing about “the best” converging lens at this point, particularly when only about $140 is at stake (price of WeMacro offering less Raynox lens). I do think there are options out there that offer a different set of trade-offs that may be perceived as better according to the needs of particular photographers (I'm one). But the alternatives I can think of are not turn-key and could easily cost ten times or more what the WeMacro/Raynox does. For a lot of photographers, a lot of the time, the WeMacro/Raynox seems like an easy answer.

Can this lens be set at infinity focus? Can’t find it.

Yawns reference is to a "Canon EF-S 55-250mm F4-5.6 IS Lens." This is a standard zoom lens for non-macro use, and as such, it should definitely focus to infinity. in the eBay auction Yawn referenced, this lens is priced at $60.

Another question: is vignetting a common issue using a microscope in combination with bellows, zoom lens, Raynox tube lens?

A cardinal virtue of the Raynox, when used as a converging lens, is that it does not vignette even on a full-frame DSLR (so certainly not on your smaller APS-C sensor). Similarly, a zoom lens such as Yawns recommended should not vignette either when fully zoomed out and with the iris wide open. If you zoom in, however, you will eventually experience vignetting. Where this occurs varies by zoom lens model. Yawns gave you his results for the lens he recommended. A bellows designed for FF DSLR should not itself cause vignetting on a FF DSLR (much less for your APS-C sensor). This said, bearing in mind that a bellows or tubes is just empty space, optics you place on the bellows may or may not cast an image circle large enough to prevent vignetting.

--Chris S.

[Deanimator]

I presume you're just beginnng ...
If I were in your place, I would get a simple 55-250 zoom (usable from 180>> )
Cheap and simple to use..., just needs an adapter for the lens mouth..

Can this lens be set at infinity focus? Can’t find it.

I don’t want the best of the best tube lens, if there is a “best”.
but don’t want to spend/waste a lot of money buying a lot of things to try out..
Just starting with a good tube lens i can use for a long time that can make decent images.

It's just a normal zoom lens, so yes it can be focused to infinity. I have the current STM version of that lens and it's an excellent medium telephoto zoom for the money in its own right. I don't have any infinite objectives so I can't tell you how well it does as a tube lens.

[mawyatt]

Like Rik and Chris mentioned, the Wemacro Vertical Stand is a good small stand that can be used vertically and horizontally (with the option). If you decide on this be sure and get an additional 1/4 to M8 adapter for a more rigid horizontal mount.

I have and use these stands since they were 1st offered a few years ago, and can speak from lots of actual use. I did a video test of an new motor/rail controller that I'm developing and used this Vertical Stand, BTW the video was at effective 800X!!

https://drive.google.com/file/d/19wE-B- ... sp=sharing

Best,

[D.d.K]

I don’t own the raynox 150 yet. Only have the 250 but I will not getting the same magnification as i’ll get with the 150 so i still have to buy the 150 too.

That lens on ebay looks pretty bad imo, but i’ve found another new lens that’s suite cheap too (half the price of the raynox 150 tube lens) but then i don’t have support brackets to keep it all sturdy..

Canon EF 75-300mm f/4.0-5.6 III
I think Greg Stephens Potter has the same lens and as I see his shots with it, it looks decent.

Because i consider to buy a fullframe in the future, this will also fit wheras the 55-250 doesn’t.

[Yawns]

Just suggested you a zoom because of flexibility .. I don't even use Canon, I have no idea.. just did a quick search for a cheap zoom... I use Nikon and I have at least 7-8 "tube" lenses...
You will find for yourself later the limitations of a rigid system with a Raynox.

[mawyatt]

Just took a quick look at Wemacro site and noted the new Raynox 150 Tube Lens (Pro). This appears to be a good solution since you already have the Wemacro Rail, and the Raynox 150 & 250 are "known" very good tube lens.

Many of us use the Raynox 150 & 250 and have had good results with various objectives. I don't have the "150 Pro", but looks like a very good solution, and coming from William at Wemacro probably is!!

Best,

[Chris S.]

Just took a quick look at Wemacro site and noted the new Raynox 150 Tube Lens (Pro).

For clarity, let's note that "WeMacro Raynox DCR 150 tube lens (Pro)" is the official name of the product that Rik mentioned above in the thread, and that I commented on. (Lest anyone think we're talking about different items.)

--Chris S.