Does it make sense to buy a 180mm prime lens for my garden?

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Originally Posted by JBW

Thanks to one and all. Seems to me that the consensus is that the 180 is to small and the 150/600 is way to big.

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I'm sure you mean 180mm is too short a focal length and the 150/600mm is too heavy a beast

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Originally Posted by JBW

Manfred's description of how he had to rig the tripod was an eye opener. It is apparently back to the drawing board.

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Whilst I have not used the Tamron 150/600mm I very regularly use the 80-400mm + 1.4TC (550mm) which is slightly lighter both hand held (weight supported on something usually) and most often on a monopod. The 80-400mm I use is also renowned for a poor flimsy tripod bracket.

Birds and critters generally have movement so a fast shutter speed is necessary to arrest that and with this there is less dependence upon tripod/monopod rigidity.

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Originally Posted by Stagecoach

I'm sure you mean 180mm is too short a focal length and the 150/600mm is too heavy a beast



Whilst I have not used the Tamron 150/600mm I very regularly use the 80-400mm + 1.4TC (550mm) which is slightly lighter both hand held (weight supported on something usually) and most often on a monopod. The 80-400mm I use is also renowned for a poor flimsy tripod bracket.

Birds and critters generally have movement so a fast shutter speed is necessary to arrest that and with this there is less dependence upon tripod/monopod rigidity.

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I'm sure I did.:) Have you ever heard of this lens? A fellow at Iceinspce suggested it.
http://opteka.com/500m.aspx

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Originally Posted by Dave Humphries

Hi Brian,

Have you tried this exercise?
Take a shot with your 90mm, placing a subject in one corner
Then crop it to quarter size (obviously the quarter with the subject in)
Now assess whether that's filling the frame enough (ignore image quality)

This will give you an idea if 180mm is going to be long enough - I suspect not - a Kingfisher (if yours are similar size to UK ones), even at 2 - 3m, is going to be pretty small in the frame.

After that, you're down to the age old compromise between limited cash, focal length, max. aperture, lens weight (on monopod/single legged tripod?) and limitations of lens availability for the Sony/Minolta mount that will Autofocus, or using another format via an adaptor.

Not sure if Sony have a tele-convertor?
That might help with focal length, albeit at the risk of forcing manual focusing (depending aperture of prime lens and your camera body's AF capabilities).

HTH, Dave

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Most of my shooting now is manual focus. I tend to stay away from Sony lenses do to cost. I will try the experiment. I just might end up with a 60mm telescope :)

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Originally Posted by JBW

I'm sure I did.:) Have you ever heard of this lens? A fellow at Iceinspce suggested it.
http://opteka.com/500m.aspx

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That looks like the Samyang f/8 500mm catadioptric (mirror) lens that is sold under a number of different brands including Opteka, Bower, ProOptic, Vivitar, etc.

The problem with cat lenses is that they are relatively slow (f/8 is hardly a speed demon) and they have terrible "donut shaped" bokeh caused by the secondary mirror. They they have a fixed aperture and you need to use ND filters to change the amount of light hitting the sensor.

The fact that none of the major lens makers offer one should tell you something. I believe Sony may have been the last majors make this type of lens; so far as I know it was discontinued several years ago. I tested a cat once and was quickly convinced that the downsides significantly outweighed any upsides for me.



http://www.samyang-lens.co.uk/samyan...rror-lens.html

Hi Brian,

I did some research a few years ago when I was into astronomy on digiscoping.
Might be worth a search to see if there might be a solution for what you want to accomplish.

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Originally Posted by Dave Humphries

I'm sure it still will be the case - adding any extension tube between lens and body will prevent it from focussing to infinity.

If you think about it, the lens was designed to focus infinity at a certain distance from the rear element and if you increase that by even the smallest tube (typ. 12mm), that will no longer be possible. I don't see how a TC will change that, but I've not tried it.

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For Dave...

What I meant was that, perhaps you do not need to place an extension tube between the rear element of your lens and the Sony teleconverter. I have to do his with my Tamron and Canon TC since the units will physically not fit together without the addition of a spacer (in this case the extension tube).

I "think" that other Teleconverters do not have the same problem as my Canon 1.4x TC.

If you did not need to add the "spacer" there would be no problem in focusing to infinity with the macro lens plus TC...

For Brian...

I think that you will find that using a telescope is pretty slow and that the image quality will not match up with your bare 90mm Tamron Macro lens...

As Manfred says, Cat lenses have an iffy reputation. Fixed aperture - f5.6 for a 250/300mm lens, f8 for a 500/600mm lens - but with today's cameras it's easy to change the ISO for more or less exposure. Bokeh? Well you either hate it or accept it! Any of the currently available lenses SHOULD have built-in/removable filters for further adjustment. But as always YOU GET WHAT YOU PAY FOR!
Here are a couple of hand-held images to maybe show that a sharp focus is quite possible (I hope...:o)
Taken between 20 and 30 ft away with a Minolta A/F 500mm cat lens.

https://g1.img-dpreview.com/BE79B8E3...0740450311.jpg

https://g4.img-dpreview.com/EC906AD5...421B1F9D55.jpg

The donut-like bokeh of specular highlights produced by mirror lenses used to be rather popular, especially when the image is a water scene displaying lots of specular highlights. Now that I have learned from this thread that fewer and fewer mirror lenses are being used, I understand why it has been so long since I have seen an image made in that style.

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Originally Posted by Cogito

...Bokeh? Well you either hate it or accept it!

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As a tangent to the fixed aperture and well known donuts: Three years ago a member of a local forum (www.foto.no) presented a DIY device for focus fine tuning his mirror reflex lens, and he also presented an aperture device for it.

The focusing device was essentially a part of a string tuner from a guitar or similar instrument. He attached a rubber wheel to the string tensioning capstan, mounted the tuner to a piece of wood that he rubber banded to the lens body. The rubber wheel rides on the focusing barrel. Turning the string tensioning screw, turns the rubber wheel that moves the focusing barrel.

His aperture device can (of course) only reduce the aperture opening from the nominal one, but it also alters the aperture shape. Two circular disks made from a black plastic folder/cover can rotate independently on a common center. Along the outer edge of each disk he cut out a banana shaped opening. When mounted on the front of the lens, the size of the matching banana openings defines the maximum opening available, rotating one disk reduces the opening as one disk covers part of the banana opening on the other disk. Out of focus highligts vary betwen long banana, short banana or circular (on par with an ordinary lens) depending on the selected opening.

Alas, the thread starter's posting and the comments are all in Norwegian, but I hope the above covers the essentials of his explanation and what can be seen in a picture he published with it.

The URL: https://foto.no/f/703539

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Odd S.

Brien. For what it's worth, I have the Tamron 70-300 with stabilization and I love it. It's fast autofocus and very sharp. Also I use a Kenko 2X TC MC7 behind it for extra range. AF is still functional. I strongly recommend image stabilization. I use the Canon 6D FF.

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Originally Posted by ragman

Brien. For what it's worth, I have the Tamron 70-300 with stabilization and I love it. It's fast autofocus and very sharp. Also I use a Kenko 2X TC MC7 behind it for extra range. AF is still functional. I strongly recommend image stabilization. I use the Canon 6D FF.

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Sony comes with in-camera stabilization.

I see that now. The Tamron without IS would still be a good choice for you IMHO.

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Originally Posted by ragman

I see that now. The Tamron without IS would still be a good choice for you IMHO.

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it's certainly one of the top choices :)

:(

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Originally Posted by JBW

it's certainly one of the top choices :)

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Brien, this was shot last night with the Tamron and 2X TC on a tripod.
http://i63.tinypic.com/s6hdvn.jpg