nnowak
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Veteran Member
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Posts: 9,074
Re: How should I resolve my birding GAS?
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User1303423862 wrote:
nnowak wrote:
User1303423862 wrote:
nnowak wrote:
Why do you need to handmake a teleconverter when there are plenty of third party EF options on the market that will directly mount to your EF 70-300mm with no modifications? A very quick search on eBay turned up several options under $50.
They won't work with more recent Canon cameras (unless you remove the printed circuit board from inside them).
Have you tested this on your M6? I am pretty sure this was only a limitation with the AF system used in the DSLRs that could only work at effective apertures up to f/5.6 or f/8.0. Even if it is still the case, soldering a few wires to bypass the circuit board is far easier than trying to hand align optical elements stuffed into an extension tube.
It is still the case. But yes, bypassing the circuit board is easier, but you don't get to shim and tune the optic to optimise its performance for the lens you're dedicating it to.
If you are not using a $10000 great white lens, modern, OEM 2X teleconverters are just OK. Decades old third party converters are definitely worse. Shimming won't change that.
Anyway, here are a couple of OOC JPGs.
These look pretty soft and low in contrast with color fringing on the edges of highlights. It would be interesting to see similar shots without the teleconverter in place since these sample were only at 94mm and 200mm respectively.
In my experience, it's pretty hard to photograph swan plumage in full sunlight without blowing out the highlights, so I underexposed the shot with respect to the background.
I was not commenting on the darkness of the background.
Please show me your contrasty swan plumage pics. It's easier in flat, bright light than direct sunlight for sure.
Again, it has nothing to do with exposure. All your images with the 2X have a dull, hazy appearance like you are shooting through a dirty window.
Start simple and compare 150mm plus the 2X converter versus the bare lens at 300mm. This will eliminate any variance from upsampling/downsampling and will most clearly show what the 2X converter is doing to the image. If you need a repeatable target with lots of fine detail, I would suggest a child's stuffed animal.
OK, I'll give that a go once I've built the new TC, optimised for the lens.
You might want to run a quick test with your current setup before you waste more time and money on another 2X.
Whilst you're here, and hopefully looking at a bigger screen this time, please have a look at Larry's TC on the 55-250 IS lens and tell me where in the image I need to be looking for the "significant degradation in image quality" you talked about last time.
The squirrel image looks a bit better than the bird photos you have posted, but part of this is likely due to being at a much lower ISO than most of your other samples. At 135mm plus the 2X converter, this is another image that could have been easily captured without the teleconverter.
You can't get a 270mm FL with a 250mm FL lens
It is more than close enough and would only require the tiniest bit of cropping to exactly hit 270mm. I am quite certain 250mm cropped to 270m will look much better than 135mm plus a 2X converter.
In general, all of the samples have this appearance of being captured through a dirty, hazy window.
Are you sure you haven't been blowing too much smoke at your screen while throwing buckets of cold water around the forum?
If you zoom in, there is just no fine detail due to the degradations from the 2X converter tied with the ISO getting bumped up 2 stops.
The squirrel's detail is fine for my kind of viewability. You can be as picky as your 2kg lens allows.
An original 100-400mm is nowhere near 2kg (1.38kg) and would not have cost much more than your 70-300mm II. Not only is the 100-400mm designed specifically to accept teleconverters, but it would have allowed you to skip the 2X nonsense altogether. The Sigma or Tamron 100-400mm are two other options that would sit between the Canon 70-300mm and 100-400mm in terms of both size and price. While huge, a Tamron 150-600mm is very close to the price of the Canon 70-300mm, especially once you add in the cost of the teleconverter and extension tube. Basically, you are trying to get more reach the hardest way possible, and not saving any money in the process. Your only real advantage over the other options is in terms of weight, but you are giving up a lot of image quality in the process.
It is the difference between capturing "a" photo versus capturing "the" photo.
Capturing "the" photo is the province of people willing to spend bigger cash cash for heavier, higher quality lenses they're willing to tote around.
As I pointed out above, there are better options that don't cost more.
I know where the compromises I'm willing to make lie and what level of fine detail I'm happy with.
If you're fine with the results, then great. As a technical exercise it is a bit interesting, but optically, I personally find the images with the 2X converter to be pretty lousy.
