Minimum Focus Distance

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DavidT

DavidT

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I am curious as to how to figure out if there is any advantage over one lens vs another when looking at different focal lengths and their minimum focusing distance.

I would like to shoot more butterflies and bees. Using a 90mm macro has its challenges as they don't tend to like you getting that close and flying away and a macro isn't the fastest focusing lens.

I have the Sony 200-600 which will focus at 600mm and 7.87' (2.4 meters). The Sony 100-400 will focus down to 3.22' (.98 meters). So if they are both used at their max focal length which one can have the subject fill the frame more? I can't decide if I want to buy the 100-400 for this purpose, it is redundant to my other gear so if it can't help in this area it isn't worth adding and spending $2,500.

I appreciate the math folks who can help out. :)
 
I think maybe the stat you want is maximum magnification. This is usually listed in the lens specs. It's not so much how close you can focus but the combination of that and the focal length that tells you how much you can fill the frame. A normal lens might range from .10 to .25 while a macro lens will get you more like .50 to 1.0. The higher the MM the more you can fill the frame. Using extension tubes increase the MM but you lose infinity focus.
 
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I do not know if Sony provide reproduction ratios in decimals for their lenses.
Nikon often does.

I hope the following helps.

If you divide 1.5 inches (for 24x36 format) by the Nikon reproduction ratio of 0.38x for the 100- 400 you get a subject size of close to 4 inches - 3.947 inches on my calculator.
Adding a 1.4 x converter provides a 2.64 inch size subject - enough magnifications for many butterflies.

Note that with zoom lenses the maximum reproduction ratio is it not always at the maximum zoom setting.

You are likely to be becoming to appreciate that more distance between the front of the lens and the subjects helps when photographing many insects.
Nikon quotes 2.64 feet from camera sensor at 100mm and 3.22feet at 400mm.

More useful but rarely quoted these days is the working distance.
The working distance is the distance between the front of the lens (without the lens hood fitted) and the subject at minimum focus distance.
 
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David

Most long lenses have large MFD - it is often better to look at a zoom with TC.

You can add extension tubes to reduce the minimum focussing distance (yes but at the cost of far distance and some light transmission). But I find this tough to Af on moving subjects.

The Z 70-200/2.8 S and Z 100-400 S have a MFD of 50cm (20") and 75cm(30") and one can add a 1.4x or 2x TC and this does not effect the MFD.
Still obviously not MACRO but one can increase magnification from 0.2 to 0.4 and 0.38 to 0.76 respectively.
 
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Usually you just need to look for the maximum magnification value which is often provided in the lens specification. I usually just search on B&H and look at the spec sheet.

For 200-600 and 100-400 the MM values are:
0.2x for 200-600
0.35x for 100-400.

Of course those magnification values are at MFD so you have to get much closer with the 100-400 in order to get that magnification benefit.
Adding a TC you just multiply directly. So say adding a 1.4TC to the 200-600 would get you 0.4x at the same MFD of the 200-600 without TC.
Adding extension tubes can get you more magnifcation but you have to move closer as it shortens the MFD and loses infinity focus. There are calculations found online to calculate how much decrease in MFD and increase in MM you get from different extension tubes.

What I don't know how to calculate is what the MM of the 100-400 would be if you shot it from the same distance away as the 200-600. So say shooting both at the 200-600's MFD (2.4m).
 
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DavidT said:
I am curious as to how to figure out if there is any advantage over one lens vs another when looking at different focal lengths and their minimum focusing distance.

I would like to shoot more butterflies and bees. Using a 90mm macro has its challenges as they don't tend to like you getting that close and flying away and a macro isn't the fastest focusing lens.

I have the Sony 200-600 which will focus at 600mm and 7.87' (2.4 meters). The Sony 100-400 will focus down to 3.22' (.98 meters). So if they are both used at their max focal length which one can have the subject fill the frame more? I can't decide if I want to buy the 100-400 for this purpose, it is redundant to my other gear so if it can't help in this area it isn't worth adding and spending $2,500.

I appreciate the math folks who can help out. :)
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FWIW, I look at both MFD and maximum reproduction ratio when evaluating lenses for wildlife and pseudo macro work, IOW stuff like amphibians, butterflies, large dragonflies, larger flowers and the like that don’t approach 1:1 scaling at the sensor.

A short MFD can be very useful for things like working from a blind where I can reliably get very close to my subjects. And maximum reproduction ratio can be very important for very small subjects that I can get extremely close to.

The two are related of course by the focal length of the lens but IMO both are worth considering when choosing wildlife lenses.
 
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Icarus said:
David, when I was shooting Sony I used a 70-200 type II with a 2x TC for insects. It was an amazingly good combo for that purposes plus the 70-200 f2.8 is useful for other purposes. :)
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I happen to have that lens and both the 1.4 and 2x tc. I will give that a try!
 
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fcotterill said:
This online calculator may help with an approximate estimate of the size of the subject

www.omnicalculator.com

Focal Length Calculator

The focal length calculator allows you to compute magnification, angle of view as well as the focal length needed for a picture of a distant object.
www.omnicalculator.com www.omnicalculator.com
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Interesting. So I plugged some numbers and at 600mm with the MFD of the 200-600 Sony the object size is about double than the 100-400 using its MFD. I think I am tracking the data correctly.

At 600mm the object size is 4.131 and at 400mm it is 2.003 using a FF sensor. So if that is the case it isn't worth buying another lens or spending $2500!
 
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DavidT said:
I am curious as to how to figure out if there is any advantage over one lens vs another when looking at different focal lengths and their minimum focusing distance.

I would like to shoot more butterflies and bees. Using a 90mm macro has its challenges as they don't tend to like you getting that close and flying away and a macro isn't the fastest focusing lens.

I have the Sony 200-600 which will focus at 600mm and 7.87' (2.4 meters). The Sony 100-400 will focus down to 3.22' (.98 meters). So if they are both used at their max focal length which one can have the subject fill the frame more? I can't decide if I want to buy the 100-400 for this purpose, it is redundant to my other gear so if it can't help in this area it isn't worth adding and spending $2,500.

I appreciate the math folks who can help out. :)
Click to expand...
The 100-400mm paired with the 1.4TC is just about the best setup I've ever used. If I want really close the 90mm is what I reach for but for everything else the 100-400 is outstanding with or without TC.
 
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DavidT said:
I have looked at the new 90 they came out with but I really don't want to add a second system unless it is medium format.
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David-
I get that. But for macro, the OM-1 and lenses appear awesome. It is not just the new 90mm. You get a .57X magnification and about 3' working distance with a 100-400 (800mm equ. reach) fully zoomed without a TC. For butterflies and moving bugs, that's great.

The increased effective f/stop that adds DOF and limits subject isolation taking wildlife shots is a plus shooting macro.

Also, to some extent you can stack a small # of shots automatically within the camera.
-Tom
 
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arbitrage said:
For 200-600 and 100-400 the MM values are:
0.2x for 200-600
0.35x for 100-400.
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This works out at 7.5 inches wide (on 24x36) for this 200-600 and 4.29 inches wide for this 100-600 - though as I mentioned earlier not necessarily at 600mm and 400mm respectively.
Extension tubes can help - a little - as at infinity focus 600mm of extension tubes is normally needs 600mm to get to 1: 1, with 400 at 400mm.

Although extension tubes contain no glass they may introduce lens aberrations, particularly colour fringing.
The reason is most ML lenses are designed to work at only one specific lens flange to sensor distance and adding tubes changes this distance.
 
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Tom Reynolds said:
David-
I get that. But for macro, the OM-1 and lenses appear awesome. It is not just the new 90mm. You get a .57X magnification and about 3' working distance with a 100-400 (800mm equ. reach) fully zoomed without a TC. For butterflies and moving bugs, that's great.

The increased effective f/stop that adds DOF and limits subject isolation taking wildlife shots is a plus shooting macro.

Also, to some extent you can stack a small # of shots automatically within the camera.
-Tom
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I agree. I often recommend the OM system to folks on here. I spent over $70K in new gear over the last two years so I have no desire to add another to the mix. It has some solid specs for some things but spending another $4K plus just isn't going to happen.
 
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I was looking at this pretty closely a month or two ago for the Nikon system. My thought process and references may be useful.

I used this database from Roland Vink as a data source. He includes every Nikon lens including the long lenses and long zooms.

At first glance, you would want to concentrate on magnification ratio at minimum focus distance. The clear winners in the Nikon system are the Z100-400 with a 1:2.6 magnification ration and a MFD of 0.75-0.98 meters (2.5 to 3 feet). The Z 24-120 is a little better at 1:2.5 and MFD of .35 (14 inches). The older F-mount Nikon 300mm f/4 AFS (non-VR) at 1:3.7 and MFD of 1.45 meters or 4.5 feet. All of the longer lenses can be improved with a 1.4 TC.

The big long lenses all fall into the 1:6-1:7 range or a little outside that. That's not a lot of magnification even at minimum focus distance with a 600mm lens.

The catch is with what happens when you move back from minimum focus distance. Just moving back 2 feet significantly reduces the magnification ratio with all these lenses, and has the most impact on the shorter focal lengths. So a 90mm macro that is 1:1 at 14 inches may have much less magnification at 3 feet and be unusable for the desired intent. So I think you need to have a common distance to subject of 6-8 feet, and evaluate lenses not based on maximum magnification, but based on a set working distance that is subject friendly.

Another misconception is relying solely on focal length. At 300mm and f/2.8, f/4, and f/4.5, Nikon has lenses ranging from 1:3.7 to 1:10. It is a lens specific design decision.

For me, I settled on the F-mount 300mm f/4 AFS - often with a TC. It gives me a good option at 5-7 feet depending on whether I use the TC or not.

I'd look for a 300mm lens or longer with a magnification ratio of 1:4 and the ability to use a TC if the subject is small critters like butterflies, dragonflies, etc.
 
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A couple of things to take into account:

1) Most zoom's focus breathe when at close-up distances. So a 600mm might be closer to 500mm at MFD. The 70-200 VR2 was kind of infamous for being about 135mm when set to mfd at 200mm...

2) Not all lenses are equal when it comes to image quality at MFD... one example from my experience was the Canon 300m L IS vs Nikkor's 300mm f4 AF-S, where the Canon was markedly inferior at close focus distances to the Nikon.

Usually zooms are better at longer working distances...
 
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Take a look at the Sigma 100-400mm, Sigma apparently makes the Olympus 100-400mm -- my Olympus focuses to 4.2" throughout its zoom range and take the TCs very well. On my Olympus camera that equates to 800mm (with the 1.4X TC that equates to 1120mm), I've been using that to photograph butterflies and it does very well --

European Skipper (d).JPG
You can only see EXIF info for this image if you are logged in.
 
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Woody Meristem said:
Take a look at the Sigma 100-400mm, Sigma apparently makes the Olympus 100-400mm -- my Olympus focuses to 4.2" throughout its zoom range and take the TCs very well. On my Olympus camera that equates to 800mm (with the 1.4X TC that equates to 1120mm), I've been using that to photograph butterflies and it does very well --

View attachment 63293
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I did look at it for Sony but the native Sony 100-400 focuses significantly closer.
 
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DavidT said:
I did look at it for Sony but the native Sony 100-400 focuses significantly closer.
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There are some potential traps when trying to calculate close up magnification.

First many lenses change their infinity angle of view when focussed close - often called focus breathing).
The magnification ratio may be needed from the manufacturer to work out how much magnification different lenses achieve at their MFD.

Second a 24x36 format body at 1:1 covers a 1.5 inch wide subject, a Nikon DX body covers 1 inch, a Canon crop sensor body a little less, and Olympus with their smaller sensor approximately 0.75 inches.
There is more magnification (for the same angle of view) with a smaller sensor body.

Whatever the MFD magnification is for a lens if it is an FX lens there is more subject magnification using it on a Nikon DX body, and even more magnification if uses via an adaptor on an Olympus body.
Going the other way an Olympus lens is unlikely to work satisfactorily on a DX body or a 24x36 body as Olympus lenses have a small image circle that is unlikely to fully cover a larger format sensor toward the frame corners.
 
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DavidT said:
I would like to shoot more butterflies and bees. Using a 90mm macro has its challenges as they don't tend to like you getting that close and flying away and a macro isn't the fastest focusing lens.
Click to expand...

Good advice here but maybe a longer macro lens is an option. That will give you a greater working distance. Sigma used to do a 180mm macro lens but IIRC it was replaced with a 150mm one.
 
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DavidT said:
I am curious as to how to figure out if there is any advantage over one lens vs another when looking at different focal lengths and their minimum focusing distance.

I would like to shoot more butterflies and bees. Using a 90mm macro has its challenges as they don't tend to like you getting that close and flying away and a macro isn't the fastest focusing lens.

I have the Sony 200-600 which will focus at 600mm and 7.87' (2.4 meters). The Sony 100-400 will focus down to 3.22' (.98 meters). So if they are both used at their max focal length which one can have the subject fill the frame more? I can't decide if I want to buy the 100-400 for this purpose, it is redundant to my other gear so if it can't help in this area it isn't worth adding and spending $2,500.

I appreciate the math folks who can help out. :)
Click to expand...
Bees may be different than butterflies. Butterflies vaary in size but most do not require full 1:1 marco for frame filling shots. I have the following two Nikon lenses and they seem comparable to the Sony in specs so:
Nikon Z 400 TC 2.8 @ 560 mm has 0.23 Magnification Factor or 6.1 inch wide field of view

Nikon Z 100-400 mm @ 400 mm has 0.38 Magnification Factor or 3.7 inch wide field of view

Sony 200-600 mm @ 600 mm has 0.2 Magnification Factor or 7 inch wide field of view

Sony 100-400 mm @ 400 mm has 0.35 Magnification Factor or 4 inch wide field of view

The heigh would be even smaller. the Sony 200-600 would have a FOV of 7 X 4.7 inches approximately. Likely enough for larger butterflies. The 100-400 would be about 4 X 2.6 inches or enough for almost all butterflies. The 100-400 lens would have a working distance of around 2 feet while the longer lens would be around 7-8 feet. To get down to smaller insects, you likely need a macro lens. I have a 105 mm macro that can be true 1:1 macro, but I scare away a lot of subjects. Still looking ofr a perfect solution. Is the 100-400 worth the cost to add. As a well known wildlife photographer often says...it depends.
 
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My experience with macro was previously with a D-300/105 (underwater) and currently with an OM Systems OM-1. Both these cameras are cropped sensor cameras and both seem to do better than a FF camera.

Take the OM-1 100-400m for example. At a MFD of 4'2" (Working distance 3'4") the result is a .57x magnification factor. If I add a 2:1 TC I am now in the 1:1 range still about with 3'4" of working distance.

I think if you want to shoot Macro moving bugs with Nikon, you would be better with a D-500/300pf and a 2.0TC

Tom
 
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