How should I resolve my birding GAS?

User1303423862 wrote:

The acid test will be at 300mm + 2X TC downsampled to compare with 300mm cropped to half resolution to get the equivalent FOV. That's what this is really about.

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 "serious degradation in image quality" you talked about last time.

That photo looks OK, but you can do better with bare optics. I know my RF 100-400mm performs better than that. Even with a 1.4x TC I’d expect it to deliver better results, although I haven’t tried that. This shot reminds me of a Canon FDn 400mm f/4.5 I used to own years ago - decent, but ultimately unimpressive and not worth the effort. It probably makes for a killer sports lens on a shoestring budget, but it’s insufficient for wildlife.

I’m abroad right now, so unable to access my photo database, but once I return I could fish out some samples to compare with yours.

Kharan wrote:

That photo looks OK, but you can do better with bare optics. I know my RF 100-400mm performs better than that. Even with a 1.4x TC I’d expect it to deliver better results, although I haven’t tried that. This shot reminds me of a Canon FDn 400mm f/4.5 I used to own years ago - decent, but ultimately unimpressive and not worth the effort. It probably makes for a killer sports lens on a shoestring budget, but it’s insufficient for wildlife.

The 55-250 is a great lens for it 375g weight. The 70-300 IS II USM I just bought is 100g heavier than your RF 100-400, but at least I can use it on both my M6 and my R. It was a lot less expensive too. The main aim of the upgrade was faster focusing for BIF.

I’m abroad right now, so unable to access my photo database, but once I return I could fish out some samples to compare with yours.

Please do, I'm up for comparisons to help drive my desire to improve my photography forward.

nnowak wrote:

User1303423862 wrote:

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.

Nice when an opportunity to grab a shot of a close by squirrel pops up while you're shooting more distant birds in flight. Didn't have time to take the TC off.

An original 100-400mm is nowhere near 2kg (1.38kg) and would not have cost much more than your 70-300mm II.

In UK an old well used copy is around £500-£700. My new lens cost £435 and comes with Canon UK warranty.
The 100-400 is twice the weight of my 70-300 (710g).
It has older, slower focusing tech.

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.

Heavier, older, slower and less accurate focusing, more expensive, no warranty.

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.

Twice the price (£900), three times the weight (2Kg), slower focusing, bulky - no thanks.
The TC and extension tube cost me less than £30 (and the optics are high quality).

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. All your images with the 2X have a dull, hazy appearance like you are shooting through a dirty window.

Optically, I'm fine with the results from Larry's excellent handmade 2X TC used in conjunction with a copy of the 55-250 lens he calibrated it for. I agree we're not there yet with the same TC on the new 70-300 lens. Whether it'll be possible to make a 2X TC behave as well on the 70-300 as Larry's does on the 55-250 remains to be seen, it's pioneering territory.

If it can be done, I'll be very happy with a lens + TC combo that weighs under 800g, reaches 960mm FF equivalent, focuses quickly enough to up my BIF keeper rate, fits under my motorcycle leather for quick stop and shoot opportunities while I'm chasing red kites around the valley, and is useable on both my M and R cameras.

Only once the optics are as good as can be achieved within my weight/bulk parameters will I spend money on the latest and greatest de-noising and image cleaning software and start doing some gentle post pro to 'wipe the windows'.

Thanks for your finely barbed criticism, it 'spurs' me on to achieve better results.

A bird feeder brings the birds to you.  Squirrels too.

m100 wrote:

A bird feeder brings the birds to you. Squirrels too.

We do put some food out for the birds in winter, watch this space.

Grey squirrels: rats with bushy tails and good PR...

nnowak wrote:

User1303423862 wrote:

The acid test will be at 300mm + 2X TC downsampled to compare with 300mm cropped to half resolution to get the equivalent FOV. That's what this is really about.

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.

I decided to go with my original idea of testing with and without the TC at 300mm, and comparing the cropped (non TC) result with the downsampled (with TC) result. This is more 'real world' for my purposes. The comparison is done in a quick and easy fashion with windows photo viewer - there may be better ways to downsample the TC image. All suggestions welcome.

The sky was dull and overcast with a slight mist. Typical British autumn weather. More testing in other conditions is needed, but this first attempt at comparing the EF 70-300 IS II USM lens with and without TC would indicate @nnowak is probably right about contrast - better results can be obtained through reduced ISO requirements and reduced glassware in optical path without it, given the resolution required for a small print or viewing on a hi-def TV screen - the two main ways I enjoy looking at my photos. To my eye, resolution looks fractionally better with the TC, but there's little in it.

In the following screenshots, the lens with 2X TC attached is on the left, bare lens on the right.

Lens + TC: f/5.6 1/320s ISO 1250 ............ Bare lens: f/5.6 1/320s ISO 250

Lens + TC: f/5.6 1/320s ISO 800 .............. Bare lens: f/5.6 1/320s ISO 200

All shots are taken at full zoom, 300mm. The swan shots are directly comparable. The subject had moved closer and the light had improved slightly in the bare lens duck shot: Displayed at 85% of full resolution to make the duck a similar size in both samples.

To reduce the colour fringing visible in yesterday's shots, I put a piece of card in front of the TC optic with an aperture hole appropriately sized for the APS-C sensor. This definitely helped, you can see there is less colour fringing on the edge of the protruberance just above the swan's bill in the TC shot than the bare lens shot. Also under the duck's bill and the back of its head/neck, although focus may be fractionally better on the bare lens shot. I'll be experimenting with a similar aperture card in the EF-EFM adapter to get the best out of using the FF lens on the APS-C M series camera.

My thanks to @nnowak for challenging my assumptions and encouraging me to test this. I'll be doing more tests in various conditions to see what works best.

My thanks also to Larry Rexley for his excellent TC, it gives me great enjoyment filling the frame with my subjects, rather than relying on later cropping. It'll still have a place in my kit bag, no matter what the further results under different conditions/processing lead me to conclude.