Does a macro lens compress?

[FeatherMonkey]

As the title really I have 105mm f2.8 macro Sigma. Now I was trying to get a path shot. On a crop body I'm supposed to be getting an apx fov equivalent to 170mm now I expected to see some distinct compression.

Am I right that macro lens have more distortion correction than normal lenses? Or am I just seeing little compression and would need still a longer lens.

[William W]

As the title really I have 105mm f2.8 macro Sigma. Now I was trying to get a path shot. On a crop body I'm supposed to be getting an apx fov equivalent to 170mm now I expected to see some distinct compression.



Am I right that macro lens have more distortion correction than normal lenses? Or am I just seeing little compression and would need still a longer lens.

'compression' is a factor of the PERSPECTIVE of the shot, (Subject Distance and Camera Elevation) and NOT a factor of the Lens's Focal Length per se.

What is a 'path shot'?

How far away are you from the Subject?

Yes, generally Macro Lenses are usually free of most distortion, BUT, the reduction or overcoming of distortion by superior lens designs has nothing to do with the compression that you see in the final image. As mentioned, compression is a as a result of the perspective of a shot.

This is a 100mm Macro Lens on a 5D Series Camera (i.e. "Full Frame"), The Subject's Face is compressed, AND the Photographer wasn't quite close to her. That's why she is compressed.



WW

Images © WMW 1974~1996 / AJ Group Pty Ltd (AUS) 1997~2015

[Dave Humphries]

Bill is correct Stef,

You can easily see the apparent 'compression effect' of using a longer focal length lens by simply shooting a given subject from further away with your 105mm lens (Macro or otherwise) - and then cropping the resulting picture in post processing to give the subject filling the reduced size frame.

Obviously this will degrade image quality though.

I wasn't sure what a "path shot" is either, I could guess, but might be totally wrong.

[William W]

see the apparent 'compression effect' of using a longer focal length lens by simply shooting a given subject from further away with your 105mm lens (Macro or otherwise) - and then cropping the resulting picture in post processing to give the subject filling the reduced size frame.

Thanks Dave. I wasn't as clear as I could have been and also I had a typo which I've fixed up now.

. . . 'path shot' . . . is that BIF?

If so then a macro lens probably is not a good idea - too slow to wind up the Auto Focus.

WW

[FeatherMonkey]

Thanks, Dave and Will.

Path shot - Sorry should of been clearer just a footpath with over hanging tree's (at work so no pics)

That's interesting so it's more an optical illusion over physical distortion? Just when I'd seen the narrowing of face features on the longer lenses and widening on wider lenses, I expected the trees to pull in a little more.

Just looking for that footpath shot with tree's compressing to give that sort of perspective into infinity(bad choice). Looks like I need to find the shot rather than trying something I can't quite get.

I'll get a sample shot up later...

[xpatUSA]

As the title really I have 105mm f2.8 macro Sigma. Now I was trying to get a path shot. On a crop body I'm supposed to be getting an apx fov equivalent to 170mm now I expected to see some distinct compression.

<> . . Or am I just seeing little compression and would need still a longer lens.

Hello Stef,

I assume that a path shot is a shot of a path, lol, but further I assume you're shooting down the path rather than across it

I just went out and took some shots of my street at 18mm, 50mm and 200mm. After cropping to make each shot frame the same part of the scene, there was no difference in "compression" i.e. the perspective did not differ between the shots.



Now, If I had repeated that exercise with constant focal length but at various distances from a reference point along the street, I would expect to see different perspectives in equally framed parts of those shots.

So, if I understand your post correctly, you need to change the "compression" by varying your distance from a reference point on the path (as Dave mentions above), not by varying the focal length - and the excellent Sigma 105mm might work for you on that basis.

[edit]I missed your last post which affects what I said above but doesn't make it wrong, IMNSHO. My street is probably longer that your path and what you see framed above is about a 100 yds from the camera to the signboard. In your case, with a footpath and overhanging trees, you'd probably start with a much wider angle lens on your APS-C Canon perhaps no more than 24mm so that close trees will be in the frame . . but then still walk back and forth relative to the end of the footpath to capture the best shot. Others may disagree - as there are several ways to skin this particular cat [/edit]

[FeatherMonkey]

Thanks Ted,

That's it sorry, crossed in cyberspace. You've got me perfectly I'll try and persist got another avenue of tree's that may give me the distance I need.

[xpatUSA]

Thanks Ted,

That's it sorry, crossed in cyberspace. You've got me perfectly I'll try and persist got another avenue of tree's that may give me the distance I need.

Just a caveat, Stef: if you do persist with the 105mm you may not get the "compression" you're looking for. Do you have any wide angle lenses in your bag?

[FeatherMonkey]

The wide lens, I'm just lacking one get stuck on what to purchase wide for crop body.

Have the 18-250 Sigma an all rounder but not stunning. Or 50mm f1.8

[xpatUSA]

The wide lens, I'm just lacking one get stuck on what to purchase wide for crop body.

Have the 18-250 Sigma an all rounder but not stunning. Or 50mm f1.8

How about the Sigma at about 22mm? (35mm equiv) should still be a bit of vignetting and slightly soft corners to help your composition with a touch of ambience. And how about trying for close sharpness with some softness in the distance? Maybe f/5.6 or f/8 + focusing a little closer to the camera than you normally would?

[William W]

. . . Path shot - Sorry should of been clearer just a footpath with over hanging tree's . . .

Thanks. Understood.

*

That's interesting so it's more an optical illusion over physical distortion? Just when I'd seen the narrowing of face features on the longer lenses and widening on wider lenses, I expected the trees to pull in a little more.

Probably more 'optics' (as in Mathematics) than an illusion as such. The mind translates what we "see" when we are at the scene; our mind doesn't allow us to always 'see' what the camera 'sees'. However, it is possible to train one's mind to avoid much of the interpretation and processing that it does

*

Just looking for that footpath shot with tree's compressing to give that sort of perspective into infinity(bad choice). Looks like I need to find the shot rather than trying something I can't quite get.

You can leverage the effect of compression for that shot by:

1. choosing a straight line of trees
2. assuming a CAMERA ELEVATION at about the midpoint of the trees' height
3. assuming a CAMERA POSITION at about 15 degrees to the line of trees
4. using as large an APERTURE as possible

Have a look a Ted's three example pictures and pretend that they are a picture of a Cricket Pitch and you are at Lords next to the sight screen at the fence, (a long way away from the Wicket) standing at ground level and looking down the pitch Stumps to Stumps.

Envisage the 'compression' between the two sets Stumps - you can't see the far set of stumps because they are blocked by the near set of Stumps.

Now walk about 20 yards around the fence - the line of the Wicket (the two sets of Stumps) are now at about 10 ~15 degrees to your eyes. You will see the Cricket Pitch as very 'compressed'.

Obviously if you walk further and you are at Square Leg (90 degrees to the Pitch) there will be ZERO compression between the two sets of Stumps.

So this is a really good practical demonstration of how CAMERA POSITION will affect PERSPETIVE.

*

Now walk back around the fence to directly behind the Stumps and think about the Broadcast Box way up high above you. It is very high and the higher it is the LESS 'compression' will be realized between the two sets of Stumps. So this a really good practical example of how CAMERA ELEVATION will affect PERSPECTIVE.

***

So in planning the shot for your 'line of trees' - that's why I made those suggestions above.

Using a large Aperture is more about 'illusion' than Mathematics - if you can get a very narrow DoF then there is more optical 'illusion' of compression because the Viewer's Eye is more assiduously drawn to a very small area of the Image Real-estate

***

These 4 elements go to make the 'compression' in a line of seagulls here:



WW

(PS and if you look closely at the Camera ANGLES (Vertical and Horizontal) in the Candid Portrait that I posted you will see that '15 degrees', twice, again.)

Images © WMW 1974~1996 / AJ Group Pty Ltd (AUS) 1997~2015

[Dave Humphries]

I like the cricket pitch + stumps demo idea Bill,

Someone ought to shoot some example shots

[William W]

^
Thanks
The example was tailored for those who (perhaps) understand Cricket - I use the example often here in AUS.
I did make examples.
It was a long time ago and on positive film.
I haven't scanned them yet.
What can I say - I have no excuse!

Bill

[xpatUSA]

I like the cricket pitch + stumps demo idea Bill,

Someone ought to shoot some example shots

Stef, my earlier suggestion to keep a constant focal length while varying the distance was unnecessarily restrictive and may have even raised an eyebrow or two around here. Especially having shown quite clearly that the focal length at a given distance is not a factor - why would it suddenly become a factor at separate distances? . . "Most illogical, Captain" . . said Spock.

So, I headed back out this morning armed with the 18-200mm and tried various distances with similar framing instead. I say "similar" because, at greater distances, stuff creeps into the frame that is not there close up. Here we are:



Now we see that the variation in perspective and in foreshortening becomes quite obvious (these views are neither cropped nor zoomed). Compare the 2D angle between the tracks and compare the ratio of the sign pixel size to that of the farthest power pole. Also at the greater distances (lower two views) we see the law of diminishing returns beginning to take effect.

[FeatherMonkey]

Thanks Bill
That makes a lot of sense, your tips have me thinking of an avenue that will be a perfect fit now to try to get the height.

Thanks Ted,
That clarifies so much to the point I now see that the wide option is really what I wanted. My problem is I know I need to go wide, either I invest in an asp-c wide or go ff(Not being in for a lot except my macro, maybe even system). Just feel I'm still a little early in the learning curve to be quite making that decision. I really ought to take 18-250mm out a bit more(Check what focal length I settle on) but think the 105mm spoils me a little, I struggle to take it off.

Once again many thanks Bill and Ted for the time and such helpful and insightful posts. Also for helping me see the error of my ways.

A test shot of what I was trying doesn't need c&c noise is terrible due to high iso and bad exposure. Now I have a few tips to try to make this work better but I may have a better location.

IMG_5344

[xpatUSA]

Thanks Ted,
That clarifies so much to the point I now see that the wide option is really what I wanted. My problem is I know I need to go wide, either I invest in an asp-c wide or go ff(Not being in for a lot except my macro, maybe even system). Just feel I'm still a little early in the learning curve to be quite making that decision. I really ought to take 18-250mm out a bit more(Check what focal length I settle on) but think the 105mm spoils me a little, I struggle to take it off.

A test shot of what I was trying doesn't need c&c noise is terrible due to high iso and bad exposure.

Now I see where you're heading . .

Here's a classic of that type:



Oak Alley Plantation in Lousiana. Been there a couple of times - they serve killer Mint Juleps

Just so it's clear, the Oak Alley shot is not mine, it is by Emily Richardson - the image is from wikipedia commons:

https://en.wikipedia.org/wiki/Oak_Alley_Plantation
.

[FeatherMonkey]

Ted... You talk about mint juleps when I'm of to put myself into a kitchen.. Much rather be sipping one of them.

Lovely pic and yep what I was aiming for.

It really was just a test shot on the way home. Only when I had a try at pp did i realise the auto iso had knocked it all the way up.

[William W]

Elsewhere, I was asked a question which is related to this conversation; in my answer I referenced this thread and particularly the photograph, above ['Oak Alley Plantation by Emily Richardson']

The question that I was asked, concerned a long indoor hallway 10ft wide and 10ft high. The question asked about the most advantageous Camera Position.

My answer basically said that what is the ‘most advantageous’ Camera Position would depend upon the VISION for the particular shot and I offered a few, (but not exhaustive), options -

> Placing the camera dead-centre (both Vertically and Horizontally) the VANISHING POINT will also be at the dead-centre AND the walls and the ceiling and floor will have 'equal' geometric importance and relevance. That would be a nice interpretation. I would like that. That would look similar to Ted's shot on the thread where there are two lines of trees - it is a symmetrical interpretation using a centre-centric COMPOSITION.

> On the other hand, keeping the camera at centre ELEVATION (5ft) and placing it against one wall would skew the Perspective and introduce JUXTAPOSITION to the GEOMETRY. I would like that, too.

> A third option would be to shoot very low, from the floor (or counter, very high from the ceiling) - AND you either employ either a centre horizontal position or from the side – that could create a sense of foreboding and/or drama. A Low Camera Angle in Cine is often used effectively for a long, narrow corridor, where there will later be drama occur.

*

In Richardson's shot (op. cit.) the camera Position and the Vanishing Point are in the Centre (Horizontally), but the CAMERA ELEVATION is LOWER than the centre point (Vertically) of the trees.

I think it is easy to see the ‘foreboding’ & ‘drama’ that the (relatively) lower Camera Elevation produces, by way of the trees creating a strong and dominate canopy that ‘sucks in’ the viewer’s eye to the main Subject.

If Richardson had a ladder and climbed up 20ft~30ft to the midpoint of the trees’ height, then the ‘compression’ would probably appear slightly stronger, but the drama of the shot would be less.

***

Stef, I think it is very important to have a VISION for the shot, even if it is a very simple vision, simple such as – ‘oh I do think that I want to try symmetry’. At least with a Vision for the shot, no matter how rudimentary, we have a foundation for a PLAN of EXECUTION.

WW

[xpatUSA]

Stef,

You might find this of interest, re: perspective and camera height AGL (Above Grade Level - civ. eng.).

http://www.sigma-imaging-uk.com/sigm...n-dp2-quattro/
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